Plenums and the wasting "option"

[barryhc]

Ok folks, were going to take shot here, at removing nitrate of course, and P to be sure, and whatever other "nasties" that we can.

I am promoting wasting plenums here, and It will be said, "that has already been tried". Yep, quite a few years ago, and no reported long term success.

The intent here is to develop a method that will allow various nutrients and compounds to be removed from a substrate, in a reef aquarium.

That substrate is subject to definition, and its particle size, depth and layering, are not likely to conform to any current or past "models" for "DSB", or "plenum".

This thread is for those who do want to run a substrate of one type or another in their reef aquarium, for whatever reason, and different reasons may require different specific solutions.

Let's start, and continue to enjoy our reef keeping hobby!

Thanks > barryhc :)

[kbmdale]

Step one: how to get the soup(P and N) out of the pot(DSB) without removing the lid (not disturbing the aerobic and anaerobic layers).

You definately have to have something in place that pulls from the bottom. A well designed manifold that has even pull across the whole bottom of the bed. The variables would be Flow rate(gph it will take to get even pull), Flow Cycle (how long can you pull without pulling o2 into the anaerobic area), Flow Frequency(How often should can it be done without hindering the DSB's process)...

should we start there?

[barryhc]

Yes exactly, that is where I have put most of my efforts so far.

There might end up being a "layering camp" and a "nonlayering camp" as a result of this investigation, and that is quite fine by me.

I am going to be in the "layering camp" for quite some time, primarily because of the "critters" that I want to keep.

Some people who are not interested in "substrate critters" may want to opt for no layering, although, I think layering is going to be valuable in both cases, just done differently.

The flow, as I said, I have a handle on this, and you are very close with the 1/4" depth per "draw" that you mentioned, probably.

It might be valuable here to develop a model that works for controlling the various "oxygenated zones" in such a fashion that the substrate is maintainable ( or controlable ), with somewhat less regard for "critters" initially.

Of course, we are also going to be wasting a good portion of "something" in the "effluent". How we "control" the "downflow" is crucial to properly managing the bacterial and chemical processes that occur within this substrate.

It is the depth of these processes that we don't know enough about, and the model that we end up with even initially, is not going to be something that any studies have been done on.

However, the "Biological Phosphorous Reemoval" thread that I mentioned previously, may be much more valuable than it would initially appear.

I have been promoting what I call "High Frequency Plenum Wasting", and it is the "small draw volume" at "high flow", that is necessary to keep the flow "balanced" across the substrate area ( and its depth ). Doing so "'often" ( High Frequency ) is what will simulate a "continuous" flow.

It won't be continuous, and this is why the above "BRP" thread may be so valuable.

I hope this hasn't been too "longwinded", let me know . . . . > barryhc :)

[barryhc]

I can get very much more specific about the flow ( how to develop it mechanicly ), whenever you like, I'm just setting up the information extra carefully here at the beginning, so that we don't get "derailed".

It isn't a problem, but we do have to carefully define what we are trying to accomplish here, and without a model that at least attempts to address the "oxygen gradation" and bacterial activity within that, we would just be "blowing smoke".

Just the same, if you would like to see the "math" so to speak, regarding the "flow", give me a "foorprint" ( substrate area ) to work with, and I will develop some flow information that is specific to that "tank substrate area".

Thanks for keeping it "moving" Kris, > barryhc :)

[kbmdale]

I have a 29g with a foot print of 30x12. That should be a good starting point.

Lets start with the lowest level in the tank the bottom and work from there.

The manifold: How many pull points should there be coming from the manifold to effectively move a burst or water (1/8" drop)?

One in each corner? or one in the middle of the back?

How would the manifold need to be laid out to get even pull..

Do you have any drawings Barry? I can draw something out if I have some idea of hole placement and flow cordination.

I was intending to use 1/2 OD PVC with the holes covered by sections of filter bag cut to fit the area over the hole.

[stugray]

barryhc,

1 - nice avatar.

2 - I installed a plenum just as in the "DSB heresy" thread. I believe in the pvc plenum with lots of holes and wrapped in landscaping fabric. Pics of my plenum are in my gallery. The plenum is in my sump only, not my display. The "layered sand" is 6-8" deep. I havent attempted to draw anything through it yet, but I am getting ready ( sump is only about 1-1/2 months old ).

I will be following this thread closely.

Stu

[kbmdale]

stugray

sounds great let us know what you get when you bleed it off. Are you going to test the sludge to see if what you're getting out? Are you going to take readings before you purge and regularly after you purge, this is VERY useful info to where this thread is going..

What grains of sand did you use at what levels? Any pertinent info on the setup would be GREAT.

thanks,
Kris:bum:

[barryhc]

Alrighty then.

I think that you can do a pretty good job on a smaller tank which yours is, with a single draw point, but being were only going to use one, let's "pull" from the center of the tank. This is not really difficult at all, and is probably the preferred for "smaller" areas.

Keep in mind here that eventually, all "piping" is going to end up with one pipe, right? So, you can accomplish the flow ( or vacuum ) gradation in many different ways.

My favorite, is to "oversize" the "feeder tubes" ( your 1/2"
I. D. PVC ). The 1/2" I.D. PVC is suffeciently oversized for most applications, and, is also a factor in the "plenum space". I,m currently sticking with the Plenum idea here myself, I believe it makes a difference. I'm not positive that this difference is good, but I think it is, and we'll have to discuss that further later, or this will become a 25 page reply!

Kris, your 30 X 12 tank has an area of 360 sq. in. outside, probably 340 sq. in. "inside".

Go to www.JoshMadison.com if you don't yet have "convert.exe"

231 cubic inches = 1 gallon. 231/340 says that you have 1 Gal. of water for each .680" ( 11/16" ) of vertical water column in your tank.

Let's say you want to "draw" 1/8" of "vertical water column", each time that you "draw". So, .125/.680 = .184 gal. that you will "draw" each time.

Ok, now I reccomend that as far as flow goes, you need "high flow", which is subjective, but let's just put in an example here.

Let's say you've decided to go with 90 gph flow through the plenum during "wasting". I reccomend that you restrict the flow by 50% in order to cause flow to be "balanced" across the substrate area. This relates to the aforementioned "manifold oversizing".

Let's arbitrairly pick a 3/64" dia. hole > .047" dia. Your PVC I.D. is .500"dia. Ok, now let's just calm down here, your 7th grade teenager can do this, just ask him/her.

So, .500"squared divided by .047"squared = 113 holes. That's not so bad. Then there is the "manifold, but it isn't much different than the "standard plenum" described by "Goemans".

This math can be worked back and forth to solve starting from different criteria.

I could write a "real formula", but everyone would "drop dead" immediately, besides, we still have to determine the recovery rate of the bacteria after "we" draw" this 1/8" of water, right?

Some of this "recovery rate" stuff, will have to be determined by experiment, but I refer again, to the "BPR" thread. This is going to give us a place to guess from.

So, what's next? Thanks > barryhc :)

[barryhc]

Hey Stu, I love your avatar, Geeze, I'm jealous, really!

I haven't wasted mine either, but I'm quite certian that "we" can do something with this, and we are right now.

Thanks, > barryhc :)

[barryhc]

Heh Stu, nice pictures, and lots of effort on your part in general too!

Please consider this, understanding my best intentions here.

It appears that your "feeder tubes" are WAY TOO FAR APART!

I really think this may have had something to do with LDRHawkes' having given up on this "system".

"Balanced flow" means "over the entire substrate area" and I really believe that the "feeder tubes" need to be "crammed in very tightly".

I don't think that you were given a good example, and these things "do happen".

Please stay with us here, and throw in the "input" as well.

Visit us again, "it's all good" > barryhc :)

[kbmdale]

Let me make some drawings of a few manifold layouts. I have some unconventional ideas I think might be useful here...:)

I'm working on it now.

I know a 29g is not a very big test system but Its empty and should be cost effecient for testing..agreed?

[kbmdale]

Barry do we agree here that the bottom 1" of sand bed is the part we are looking to purge?I feel that thats the point that the build up starts, so thats the point that needs fitlering to avoid the buildup and allow the upper sandbed to continue its processing.

[barryhc]

I have Cad drawings of mine, but I haven't got the "gully-dern" conversion thing happening yet.

Exactamundo on the 29 gal. ! . . . And I don't think it is the least bit too small to draw conclusions from either. We are doing this to put together a system for "reef keepers", right?

What size tanks do reef keepers have, heh?

Kbmdale:
Barry do we agree here that the bottom 1" of sand bed is the part we are looking to purge?I feel that thats the point that the build up starts, so thats the point that needs fitlering to avoid the buildup and allow the upper sandbed to continue its processing.

Whoa! Let's be very careful here. I agree that the bottom 1" is where we start "building the system", but, let's be careful here.

The area ( or depth zone ) that we waste needs to contain the nutrients and compounds that we are interested in wasting, agreed?

It is our job here to determine where these nutrients exist in a substrate model, and how we modify the "water column flow" and the "substrate model", in order to achieve our objectives.

Please review posts #1,3,5, and 7 in this thread( even just for 5 min. in total ), and respond to 3 or 4 items that I have proposed as being important to this investigation, so that we can proceed on some kind of "even keel" here.

If we squirt ahead too fast, we will lose a lot of what we are trying to accomplish. I have considered your posts that I have read ( on other threads ), and that is very, very many posts.

I trust you, so don't let me perturb you unreasonably here, but I need the feedback in order to answer your questions accurately, and I go to consideranle lengths to do just that!

You are on the right track ( no doubt ), and you are really "right on" here, but I don't care to repeat myself a lot, and you might be able to help me here.

Now, the particle size ( or grain size ). as well as the depth of the substrate bed, including any specific "scheme" of layering is going to determine at what depth these bacterial-chemical reactions occur.

Further, the "draw" frequency and volume ( duration ) are crucial to success with this system., and also effect this "depth".

We have to be designing this system to create and or accomodate these processes and control the depth at which they occur, so that we can "waste" the "things" that we want to waste.

We are also looking to improve the the "diffusion" that occurs near the substrate surface and back into the "water column".

Yes, all of this is entirely experimental, at this point, and I do apologize to you Kris, for getting so windy "again".

The shorter answer is that I would like to see the bottom 1" and the plenum after that, be the area where the "buildup starts".

I,m not trying to filter it though, just "waste it"!

And yes, then we can allow that "upper substrate" to continue its processing.

Actually, I happen to be leaning towards the "somewhat sandbed like" upper substrate version, that you appear to prefer. I think I do as well.

If we do any good here, it is going to take a while, but it is certianly worth it. Many people are likely to become involved in this thread, and if we don't wan't it to dissolve into a "war" we should be fairly concise.

If you will respond to answers that I have given previously, my answers will become very short indeed.

Thanks again > barryhc :)

[barryhc]

Ok, I'll try a different approach here. The "buildup" only starts there, if we arrange to "put it' there. This my point. Let's figure out how to put it there, and then "waste it".

Let's figure out how to put it there, with a substrate at the surface that we happen to prefer or enjoy. Maybe even for the benefit of the "critters" if that's what "we're" into, or not. if not.

I hope that's better, I have to apologize sometimes for being "anal", or whatever.

Thanks again, really! > barryhc :)

[kbmdale]

Ok . I didn't mean thst was the main goal of the system. Just the goal I was trying to accomplish in the first layer. To remove the Waste that settles deep within the bed. There are many many variables that will be brought into play and multiple other goals that will need to be met before the system will be successful..:)



Here is a quick little concept for a manifold. Now its open for all input, change, or redesign that might be needed to accomplish its goal, so I am not 100% sold on it, just a starting point.

http://i2.photobucket.com/albums/y40/kbmdale/manifold.jpg
the red lines represent the intake holes.

the idea of it being away from the sides was so that nothing couls be trapped between the wall of the tank and the intake itself.

This was just drawn up quickly in adobe. I have access to solid edge and can make a 3-D model with a little help from a drafting friend from work.. :)

whatcha think?

[barryhc]

Well it's not bad at all, and a definite improvement over the "Hawke" design.

Try putting a "central intake" at the center of the tank, it really isn't difficult at all, just move your "rear tee" forward, to the center, then run a "line" from there to the left and to the right.

Run "legs, or "feeder tubes"from the center", towards you and away from you, with caps on the ends.

This keeps all extremity distances relatively short, and evenly balanced.

You could use reducing "manifold dias." to balance flow, or even drill larger holes as you get farther away from the "center" or "draw" point. The "oversized manifold with restricted flow" method is easier.

You have not asked about the "flow restriction" that I explained previously. You will be asking questions shortly that require that as part of the answer. It is absolutely crucial to the mechanical design of this system.

"Review-response"? Thanks for keeping "it up" > barryhc :)

[kbmdale]

That I will need help on. I am not quite sure how to get the flow to pull evenly through one outlet. Please elaborate:)

[barryhc]

You absolutely have to consider the "recovery rate", of the bacteria in this experiment, and tie that to the particle size, the depth of substrate, any layering that is going to be utilized, and then, of course, the Volume( "draw depth" ) and Frequency of the "draw".

If you don't, you are just throwing glass marbles at a "brick wall"!

If anyone tries to use this without considering the above, then they had best setup 20 tanks, with 2 sets of 5 tanks as controls, and then 5 versions with two tanks each as models.

It will all blow up certianly, even if you were to try the above.

Our only chance here is to consider these variables very carefully, and then take 1 or 2 shots at it. Even then, nobody will know that much for sure, until at least several years have gone by.

If we are lucky, or did our homework ahead of time, we may be able to report, that things are working smoothly.

Mr. Hawke claimed it was the greatest thing since sliced bread, and then gave up on it after 9 mos. or so. That is not going to happen to me.

Don't get me wrong, I started this thread, but "magic bullets" do not exist, and "plenum wasting" will not be one either.

Thanks to all, > barryhc :)

[kbmdale]

so as an "experiment" to try figure out a few variables like rate of pull and sand depths. For a starting point. What if I took a 5 gallon bucket, put a 1/2" piece PVC in the bottom that goes through the bottom. About 1/8" sticking up in the inside of the bottom. Then lay a layer or 4mm CC or Sand then screen then start with 8" of 1-3 mm sand on top of that.

Then I can put a gate valve at the end of the pvc and fill the bucket with water. See how long it takes the water to drain through the substrate with a gravity pull. I could play with the depths and record the rates.

Does that sound like a reasonable way of judging how the water level will drop pulling water through the substrate and the give us an idea of how easy or hard we will need to pull. :)

it wouldn't be an exact but an idea of what will happen.

[barryhc]

OK, but if you don't give some response to the previous posts, you will make my two little fingers bleed( the typing ones ).

If I start answering your questions without knowing if you understand the previous information, then we are doomed to a "cluster shuck" here.

I gave you about half of the "flow math" before, I cannot proceed without knowing if you understand that portion. Seriously.

Flow "durations" are going to last in the "range" of probably about 5 to15 seconds maximum, this is not arbitrary, it has to do with "bacteria recovery" times VS "Total Monthly Draw".

This "TMD", needs to be within the range of monthly water change volume, Unless of course you want to get silly with it.

Remember, we are talking ( thus far ) about throwing this stuff away.

Please bear with me here, but I cannot proceed without specific response to solutions that I have offered. I will explain it again as well, as long as you "specify" the portion that you are not comfortable with.

Let's go! > barryhc :)

[barryhc]

Kris, I can spell it out for you exactly, and I have already done so for half of the math. I'm trying to be ready to give you the other half. I'm trying to have "you" ready. Get it?

We're "crossing each other" too, as well. Each post is one place out of prooper position, because niether of us can type at the "speed of light".

I hope that was faster, nowl let's try again.

Thanks, > barryhc :)

[kbmdale]

[QUOTE]Originally posted by barryhc
You absolutely have to consider the "recovery rate", of the bacteria in this experiment, and tie that to the particle size, the depth of substrate, any layering that is going to be utilized, and then, of course, the Volume( "draw depth" ) and Frequency of the "draw".

I 100% agree. Remember this has to be done without changing the anaerobic and aerobic relationship of the zones in the bed. This will be the dictating factor in "flow" of and the amount wasted. If this is correct then I understand.


Mr. Hawke claimed it was the greatest thing since sliced bread, and then gave up on it after 9 mos. or so. That is not going to happen to me.

Don't get me wrong, I started this thread, but "magic bullets" do not exist, and "plenum wasting" will not be one either.

by taking it one step at a time we should be able to accomplish what was set out to be done.

I tend to like to find a starting point and experiment :) The math could be correct, but we have to account for the thickness of the substrate and the flow it will allow. My experiment should give some encite to those 2 variables. Agreed?

[barryhc]

Yes exactly, Kris. we are still passing in the night here, based on typing speed. As I have already stated, I can just about spell that ou for you, and this portion of it "should not be relegated to a consideration of particle size or bed depth, UNLESS, you want to waste by gravity.

I'm not recommending this, and I have reasons.

How close have we gotten to that 25 pages anyway.

> barryhc :) I just heard the "dinger", I think I'm going to die laughing!

[kbmdale]

anyone esle got any input fel free.

Barry, I got to get off for the night. Got some stuff I need to get done for work..arrggg...lol

later

[barryhc]

No Kris, I don't like that method or the experiment. Here is why.

You will not know anyhting meaningful from a "draw test" unless you draw through th "Plenum or waster" that you have built.

Especially if it is "gravity flow". We are going to have a "draw duration" that will probably be between 5 and 15 seconds, based on "bacreria recivery rates".

It needs to have "high flow", which may be beyond what gravity can deliver. Plus, how are going to control "draws" that occur for as little as 5 seconds possibly?

See what the consideration is here? > barryhc :)

["Umm, fish?"]

Can I get in on this, too? I've been in conversation with Stu since the weekend about following this sort of idea. I have some questions for you all, though.

1. Is anyone concerned that what we are setting up here might turn into the nightmare we are trying to avoid? That is, we have, in essence, plenums of a sort (still, stagnant water in the pipes) with very small diffusion point. On the other hand, the water in the pipes will be taking trips periodically away from the sand beds, so the point may be moot.

2. Since the problem we are talking about (organics leeching from a DSB) is a problem that shows up, if at all, at roughly 4-5 years into the DSBs lifespan, how often does a sandbed need to be drained, really? Would it be better to do a fairly thorough bed drain very occassionally and allow the tank a mini-cycle? I know the point is to make this as easy on the life in the tank as possible, but I'm still trying to wrap my head around the time span necessary.

Thanks and thanks for this thread.

Andy

[barryhc]

I 100% agree. Remember this has to be done without changing the anaerobic and aerobic relationship of the zones in the bed. This will be the dictating factor in "flow" of and the amount wasted. If this is correct then I understand.

No, I really do not think so. You absolutely must carefully read this thread from the beginning, or we will definitely become lost. I think we may be already.

The existing conditions in a "sand bed" are the subject of very much debate, and controversy, but not enough consideration. I am not at all convinced that we "should be" replicating a "sandbed" and then putting a "plenum" underneath it.

I have stated to the contrary ( for the most part ) since the beginning of this thread.

That is just too easy, Kris, and it won't work. I can explain why, if you wish. You will have a serious channeling problem!

We can achieve something here, let's do so. you absolutely must read this thread carefully, or my responses simply won't answer your questions.

Let's try again tommorow. Yhanks > barryhc :)

[barryhc]

Yes you can.

"Umm, fish?":
1. Is anyone concerned that what we are setting up here might turn into the nightmare we are trying to avoid? That is, we have, in essence, plenums of a sort (still, stagnant water in the pipes) with very small diffusion point.


No. You need to explain about this "very small diffusion point". I don't understand your meaning here, but I doubt it.

2. Since the problem we are talking about (organics leeching from a DSB) is a problem that shows up, if at all, at roughly 4-5 years into the DSBs lifespan, how often does a sandbed need to be drained, really? Would it be better to do a fairly thorough bed drain very occassionally and allow the tank a mini-cycle? I know the point is to make this as easy on the life in the tank as possible, but I'm still trying to wrap my head around the time span necessary.

Very often, if you want it to do something other than what a sand bed does. I have stated since the beginning, and I will continue to do so, that this "Plenum Wasting" of a substrate is not a DSB, and it is not a PLenum, by any existing standards.

Now, go back to the beginning, like I have been explaining to Kbmdale, and READ IT ALL!

I have already covered at least the next 50 questions that are going to be asked. Go read the answers, they are already there.

Thanks for joining the thread, read it. > barryhc :)

["Umm, fish?"]

No. You need to explain about this "very small diffusion point". I don't understand your meaning here, but I doubt it.

Very small diffusion point = the size of the holes in the PVC. As opposed to the open diffusion between plenum and sand bed with a normal plenum setup.

I have read the thread and I'm very excited about it. This thread, however, does not start from the beginning. There is, in your head, a defense of the idea. Unfortunately, I do not have this in my head yet and that is why I have questions about fundamentals. And, unfortunately, I'm pretty whacked on cold medicine at the moment. I'll try again in the morning.

Thanks.

["Umm, fish?"]

I just read through the phosphate wasting thread you mention. It's all very interesting info. I have a quick (and probably silly) question: DSB are very efficient at taking us through the nitrogen cycle, but can't do anything about phosphate removal. Fine. Accept the limitations of the filter along with its successes. Now, we need to get P out of the system and you are talking about culturing and harvesting the phosphate locked inside bacteria before the system becomes overloaded and the P is leached into the water column. (Or, at least getting it into the water column so a skimmer can do the harvesting.)

Fine, but isn't there already an effective means of P binding and removal from our systems? Isn't that the point of macroalgae 'fuges (binding the P into the body of the plant and removing it from the system by harvesting)? Why is it necessary to move to micro-harvesting?

Thanks. And I hope the fundamental questions aren't too much of a distraction.

[CaptiveReef]

Hello everybody,

It's a great concept, but with the manifold design it would have to be the slowest flow possible, for example 60-90 drops a minute of water mass flows through a Nitrate tower. Any faster and you bring in oxygen which upsets the bacteria that handle Nitrate breakdown.
This would be regular flow as well as reverse. Diffusion works so slow, this duration process controls the amount of new water that is introduced to the Plenum/DSB.
A DSB will not remove Phosphates, The only natural source I have found is macro algae, you get rapid growth when there is Phosphates in the system, also you have to give the macro algae a night phase just as in nature.
These conditions allow for rapid growth of the macro's which in turn the rapid growth increases the plant's need for Phosphate.
At this point any Phosphate is ripped out of the water and the consumption rate exceeds the production rate, now at this point any Phosphate production is taken care of.
You now can do monthly pruning of the macro's to allow the lower layers of algae to get light and continue the rapid growth.
To be honest I do not vacuum any waste out of my system, or my vats, The micro fauna in the sandbed and amphripods just use everything.
Also when waste is allowed to break down, it is converted to it's final form which is amino acids.
Now when we talk about our systems the waste amounts are not huge, due to the fact we are using skimmers, carbon, macro, water changes, the left over waste levels are small and is used by the micro fauna.
I just tested my system for Phosphate, and it was 0. And that's with the practices I follow.
Plant life is the best natural Phos binder as well as using Phos-Ban.


:D CaptiveReef

[barryhc]

"Umm, fish?":
Very small diffusion point = the size of the holes in the PVC. As opposed to the open diffusion between plenum and sand bed with a normal plenum setup.

I really don't quite understand what you're saying here, about "diffusion" at the holes in the PVC.

Normal "plenums do not use "sand", they use 2-4mm gravel primarily, according to "Goemans and Gamble".

"Umm, fish?":
I have read the thread and I'm very excited about it. This thread, however, does not start from the beginning. There is, in your head, a defense of the idea. Unfortunately, I do not have this in my head yet and that is why I have questions about fundamentals. And, unfortunately, I'm pretty whacked on cold medicine at the moment. I'll try again in the morning.

Where is the beginning? What idea do you think that I am defending?

I am trying to discuss the fundamentals, but not the fundamentals of "conventional Plenums". I believe that one version of "plenum wasting", which is currently my favorite, is the High Frequency type, that simulates to a degree, "continuous wasting".

True "continuous" wasting is highly problematic in terms of "flow balancing", and I think that makes any "continuous" system just about impossible to make function correctly.

Thanks for your input. > barryhc :)

[CaptiveReef]

barryhc,

With this continuous waste theory, it's being broken down at a rapid rate that is why there is a buildup of Phosphate.
If I'm reading this correctly you are trying to design a system that will diffuse and allow for waste to be washed away, to be removed with a DSB/ Plenum application.
The only design I can think of allowing this to work would have to be installing an uplift tube in the Plenum through it to the bottom connect it to the manifold, then using a quick draw to quickly remove waste buildup from underneath the Plenum. The same would go with the manifold installed in the DSB. Both would have to be a quick draw, then stop otherwise oxygenated water would be drawn into both style beds.
It could work, with the DSB I suggest putting a layer of screen covered egg crate on top of the 1st 3 inches of sand that has the manifold buried in it, then place the rest of the sand on top of this screened egg crate. The waste that will diffuse into the area of the egg crate will be drawn faster than having to be pulled through a solid depth of sand.
Also at the hole points of the manifold is where you are going to get the greatest build up of waste, these draw points may need a reverse flush from time to time to loosen packed waste.

:D CaptiveReef

[barryhc]

There simply are no fundamentals for "Plenum Wasting", we are trying to develop them here.

There is no system to defend. I have not started the "wasting process" in my installed plenum yet. I don't have any data for plenum wasting yet, and I don't yet know of anyone who has.

In the mean time, it is my current point of view, that "drawing" water from the plenum, will affect the bacteria colonies in the "substrate above it for better or worse, so we need to make it for the better.

That takes a bit of consideration, and I have considered it a lot. I am going to consider it a lot more too.

CaptiveReef:
This would be regular flow as well as reverse. Diffusion works so slow, this duration process controls the amount of new water that is introduced to the Plenum/DSB

Watch about calling this a "Plenum/DSB". Some people may want to try that, and I'm all for it, if it can be made to work. I highly prefer to call the "stuff" above the plenum, "substrate".

2-4mm gravel( standard plenums ), is not sand, and the gradation of the substrate will need to be conducive to accomodating several factors.

The use of typical "sand bed" particles could cause a good bit of channeling difficulty at some 4-6" depth, and would certianly require some grade layering in order to avoid problematic "particle migration".

Plenum Wasting is not a "magic bullet" and other systems are necessary to compliment any well kept reef. Good flow is also of paramount importance, the list goes on . . .

Thanks, > barryhc :)

[kbmdale]

The eggcrate incorperated might need to be looked at. If I understand what you are getting at captivereefing, you are saying that the space the eggcrate will create may be enough to reduce the risk of o2 getting into the anaerobic zones we want to keep in the lower layers of the "Substarte"

Have you tried this? Very interesting. any reading on that?

[barryhc]

Now were getting there Captivereef. Our replies are passing each other here, causing mine at least to look a bit "odd".

I agree generally with your post including the egg crate, and I will respond later, it sounds pretty good.

Now if I just got this one out fast enoufh . . .

Thanks again. > barryhc :)

["Umm, fish?"]

Thank you. The discussion of fundamentals on the 2nd page has helped sort things out in my mind.

The general definition of "plenum" in my head is "a layer of still water under substrate." While what you are discussing here is nowhere close to a classic plenum implementation, the water inside the PVC is still (when you are not flushing) and so fits my vague definition above. But, you intend to flush very often, so the point I was trying to make is moot.

In the implementation I intend to make, I will be using the manifold more as a DSB drain (with infrequent drainings), so I think I need to worry about the still water inside the pipes more.

Anyway, thanks again and I will be fascinated to see what results you come up with. And, if you convince me on the efficacy of frequent flushings, I will certainly give that a try, too.

Andy

[barryhc]

By CaptiveReef:

With this continuous waste theory, it's being broken down at a rapid rate that is why there is a buildup of Phosphate.

If we move the "entire water column" down, from the top of the water, to the glass at the bottom of the tank, and the distance we move this water is, say, 1/8", and that is 1 pint of water, and it takes about 5 seconds, and then we leave it alone for 8 hours, what is the effect going to be on the bacteria?

I have to start here. > barryhc :)

[kbmdale]

Originally posted by barryhc


If we move the "entire water column" down, from the top of the water, to the glass at the bottom of the tank, and the distance we move this water is, say, 1/8", and that is 1 pint of water, and it takes about 5 seconds, and then we leave it alone for 8 hours, what is the effect going to be on the bacteria?

I have to start here. > barryhc :)

That is the Question that alot of other questions I have hinge upon. HOw do you figure that one out? I know a great chemist that could probably help but last time I asked him anything my brain hurt for 3 days after the answer he gave me....lol

[barryhc]

by CaptiveReef:

If I'm reading this correctly you are trying to design a system that will diffuse and allow for waste to be washed away, to be removed with a DSB/ Plenum application.

Well yeah, pretty much. I think though, that it is "fairly likely" that most bacteral activity in a "traditional sand bed" occurs rather close to "the top". Maybe something like the first 1" of depth or so, for "most" of the activity. This would be of course, unless that is modified with the addition of cukes, stars, and various other critters, and we can take that into account as well if you like.

Below that however, I think that the processes that are going on are less important to "real-time" water quality in a DSB, and may very well represent a good portion of the "sink", that is often referred to. "The deeper this is, the longer it lasts" syndrome, so to speak. I'm not certian about this, it is just speculation on my part.

I'm not bashing DSB's here, I don't do that, and I don't have any "side" to be on.

"If", anything is collecting in the lower parts of any substrate in a reef, we might want to "get rid" of some of it. If we start wasting water, and whatever is in it, we need to do so in such a fashion that is of benefit to the bacteria that are above this wasting.

"Occasional wasting" concerns me regarding what happens to these bacteria populations, if we draw water down by say an inch or more at once.

Ok, I'm getting off subject a bit here.

by CaptiveReef:

The only design I can think of allowing this to work would have to be installing an uplift tube in the Plenum through it to the bottom connect it to the manifold, then using a quick draw to quickly remove waste buildup from underneath the Plenum. The same would go with the manifold installed in the DSB. Both would have to be a quick draw, then stop otherwise oxygenated water would be drawn into both style beds.
It could work, with the DSB I suggest putting a layer of screen covered egg crate on top of the 1st 3 inches of sand that has the manifold buried in it, then place the rest of the sand on top of this screened egg crate. The waste that will diffuse into the area of the egg crate will be drawn faster than having to be pulled through a solid depth of sand.

Well, I think I see where you're going here. This a long way away from where I'm currently at, but let's go with it anyway, for now.

I agree 100% with the "quick draw". The reason for the short duration is to have a "shallow draw depth", in order to avoid "unduly" disrupting the bacterial activity.

After that, however, I'm getting lost here, as to what the advantage is going to be from "drawing " from the middle of the substrate depth. I see how it evens the flow for you, and avoids some portion of the potential channeling problem, but, I just don't understand how you get bacteria down to the bottom of the bed, if you are "pulling from the middle".

I suppose, that you could "draw" even amounts of water with even frequencies of wasting, but now you are drawing both "up from the bottom", and "down from the top" at the same time, with the manifold in the "middle". That's pretty wild, and I thought my approach was admitedly a "bit messy". :lol:

I agree wholeheartedly about the "occasional reverse flush", RIGHT ON!

Thanks again > barryhc :)

[CaptiveReef]

Originally posted by kbmdale
The eggcrate incorperated might need to be looked at. If I understand what you are getting at captivereefing, you are saying that the space the eggcrate will create may be enough to reduce the risk of o2 getting into the anaerobic zones we want to keep in the lower layers of the "Substarte"

Have you tried this? Very interesting. any reading on that?
Yes you got! It would be a more controlled environment by having that space. I have experimented with this when I designed a filtration system to raise larval marine fish. I needed a way to filter a tank without any danger of sucking up the fish, but still be able to maintain full spectrum filtration.
Here is a drawing of the tank design and I will be posting an operating one shortly.
http://img.photobucket.com/albums/v344/CaptiveReef/larvalfilter.jpg

:D CaptiveReef

[barryhc]

God you're good Kris! That is however where we are at, and I think that there is some information out there on this as well.

I've read some, but only opinions so far, not something more concrete. If you take a peek at my last post to CaptiveReef, you will see that I made some speculation about this.

There may in fact, be some very good information on this.

I may not be right, but I continue to speculate, that a good portion of many sand bed depths, actually do "sink" a lot of conmpounds, and they eventually become a problem in some cases, usually over a long period of time.

So let's just throw out some of that lower stuff, and enjoy it, heh?

Let's be careful while we are doing it, that we keep our flow balanced, draw short distances so we don't kill the bacteria, and do it on a regular basis, so our reef is "stable".

Thanks > barryhc :)

[barryhc]

Nice diagram CaptiveReef. It makes a lot of sense to me. That is just what I have been proposing, except for feeding it continuously to a skimmer.

Where is your design at now?

Thanks for the info. > barryhc :)

[CaptiveReef]

After that, however, I'm getting lost here, as to what the advantage is going to be from "drawing " from the middle of the substrate depth. I see how it evens the flow for you, and avoids some portion of the potential channeling problem, but, I just don't understand how you get bacteria down to the bottom of the bed, if you are "pulling from the middle".


Thanks again > barryhc :) [/B][/QUOTE]
The natural diffusion will bring the waste to the egg crate level, then you are able to draw from it from below, having this egg crate space will make it easier to collect the waste for the draw and protect the upper levels from having to much oxygen drawn in. You can now have a draw level, and a functioning DSB or Plenum.

:D CaptiveReef

[CaptiveReef]

Originally posted by barryhc
Nice diagram CaptiveReef. It makes a lot of sense to me. That is just what I have been proposing, except for feeding it continuously to a skimmer.

Where is your design at now?

Thanks for the info. > barryhc :)
I have all the materials, I'm actually going to add water this weekend. I'll post pics of this project while it's under construction.

:D CaptiveReef

[barryhc]

I installed one of these in my 27 gal. hex tank 4 months ago.

I have not started "wasting" yet.

I still am curious if you intend to feed the "efflurnt" to the skimmer.

> barryhc :)

[CaptiveReef]

Originally posted by barryhc
I installed one of these in my 27 gal. hex tank 4 months ago.

I have not started "wasting" yet.

I still am curious if you intend to feed the "efflurnt" to the skimmer.

> barryhc :)
The water from the bed 1st goes through the skmmer then it goes into the power filter, on the other side of the skimmer is an elbow to direct the skimmate into a hanging cup, the power filter does all the drawing.I have to use a small power filter because you are limited to how fast the water is able to go through the substrate. Also dealing with larval marine fish and inverts, they are pretty much floating blobs until they morph into something a little more solid, so gentle water movement is what I'm looking for.


:D CaptiveReef

[kbmdale]

Here is a decent read with some of the same principles we are trying to apply..

http://www.reeffrontiers.com/forums/archive/index.php/t-2931.html

Barry you might have already read it.

[haid]

I have also been thinking about some of this. What I was thinking however would be to get some flow without oxygen into the bottom plenum, thus doing your mixing. Then use a metering pump to continuously draw water from the plenum. This should stabablize any rapid changes in the bacteria levels. I was trying to come up with a good way to seperate the anoxic layer and the aerobic layer. I was thinking something along the lines of what a reverse undergravel filter would do. Use some real fine sand above the plenum (to house the aneroxic) then have a space of some sort (maybe manifold/undergravel here) then a larger grain size for the top layer. Continually wasting from the plenum and occasionally back flushing the top larger grain substrate. This should leave the aneroxic layer alone while allowing a lot of detritus to be pushed from the larger grain anerobic layer above. The skimmer could then remove what is pushed into the water column. Just what I have been thinking.

[barryhc]

By CaptiveReef:

The water from the bed 1st goes through the skmmer then it goes into the power filter, on the other side of the skimmer is an elbow to direct the skimmate into a hanging cup, the power filter does all the drawing.I have to use a small power filter because you are limited to how fast the water is able to go through the substrate. Also dealing with larval marine fish and inverts, they are pretty much floating blobs until they morph into something a little more solid, so gentle water movement is what I'm looking for.

So flow through the substrate is equal to the "outflow" of the power filter?

This flow is "continuous"?

Is this affecting the oxygen level in the "substrate"?

Thanks again. > barryhc :)

[CaptiveReef]

Originally posted by barryhc
By CaptiveReef:



If we move the "entire water column" down, from the top of the water, to the glass at the bottom of the tank, and the distance we move this water is, say, 1/8", and that is 1 pint of water, and it takes about 5 seconds, and then we leave it alone for 8 hours, what is the effect going to be on the bacteria?

I have to start here. > barryhc :)
The area we are really concerned with is the top layer of the DSB or Plenum, that pint of water can be constantly moved from the water column to the top of the bed at a rapid rate,( the normal flow a powerhead would create), but it's the rate it goes through the bed, a 5 second draw through the bed would destroy the environment for the bacteria, the 8 hours after would not even matter with that pint of water. There has to be natural diffusion in the bed up to that eggcrate level, then a 5 second draw can be made without effecting the upper levels.

:) CaptiveReef

[barryhc]

Yes Kris, I read all of it. Did you notice that the thread "died" in Nov. of 2004?

Everyone got "bogged down" in "detritus removal" and nothing got tried or reported on.

I can handle detritus removal at the surface pretty easily, so that thread just wasn't offering anything for me.

They never really adressed the issue of maintaining an advantageous "oxygen gradation" in the substrate, or what particle size, bed depth, flow rate, layering, frequency or volume of "draw", etc.

Oh well. > barryhc :)

[CaptiveReef]

Originally posted by barryhc
By CaptiveReef:



So flow through the substrate is equal to the "outflow" of the power filter?

This flow is "continuous"?

Is this affecting the oxygen level in the "substrate"?

Thanks again. > barryhc :)
Yes the flow is equal and continuous, I'm using the substrate as a pre-filter, there is a divider wall that has a DSB on the other side. Using a very small under rated powerfilter I'm able to create the constant draw through the substate, then directly into the skimmer then into the powerfilter, back into the tank.


:D CaptiveReef

[barryhc]

By haid:

I have also been thinking about some of this. What I was thinking however would be to get some flow without oxygen into the bottom plenum, thus doing your mixing. Then use a metering pump to continuously draw water from the plenum. This should stabablize any rapid changes in the bacteria levels. I was trying to come up with a good way to seperate the anoxic layer and the aerobic layer. I was thinking something along the lines of what a reverse undergravel filter would do. Use some real fine sand above the plenum (to house the aneroxic) then have a space of some sort (maybe manifold/undergravel here) then a larger grain size for the top layer. Continually wasting from the plenum and occasionally back flushing the top larger grain substrate. This should leave the aneroxic layer alone while allowing a lot of detritus to be pushed from the larger grain anerobic layer above. The skimmer could then remove what is pushed into the water column. Just what I have been thinking.

Haid, I think your starting to get into my particular area of interest here, by discussing the "oxygen levels" ( or gradations ), in the substrate.

However, I think the term "Aneroxic" is exceedingly dangerous!

Aerobic > Lots of oxygen > maybe up to 80% saturation near the substrate surface.

Anoxic > Not very much oxygen > I haven't seen any good definitions.

Anaerobic > Devoid of oxygen.

These terms, Anoxic and Anaerobic, get thrown around a lot, but it is really hard to tell, a lot of the time, what the person using the term, might actually mean by it. Seriously!

The "Goemans and Gamble" cdrom, "New Wave" makes a careful distinction of these terms, and it is an interesting read. It is "Ungodly" lengthy, and I don't necessarily subscribe to many of the Proposals made in that 'Ebook".

You might actually be making a good point here, but I have to point out the distinction of these terms, before I can consider it more seriously.

I'm hoping you might have meant "Anaerobic".

Did I get lucky? > barryhc :)

[barryhc]

By haid"
Continually wasting from the plenum and occasionally back flushing the top larger grain substrate.

I believe that any kind of "true continuous wasting" causes a mechanical "nightmare" for "flow balancing".

Read the thread from the beginning if you want a more thorugh explanation of flow balancing, and why "short duration draws" will keep "downflow distances" within a range, that the bacterial populations can thrive in, instead of "suffer from"!

Nice to have you here. Thanks > barryhc :)

[haid]

barryhc,


Yes, Anaerobic is what I meant. Sorry not always great with terminology. I would think this method would allow you to keep the top layers from going anaerobic(pushing water up and through from the column), reduce the load on the sandbed to begin with, with less large particles there to break down. The phosphate should migrate most of the time to the bottom plenum and be wasted in a slow continuous manner. In effect draining water for small but continuous water changes.

[barryhc]

Well, "haid", that's pretty interesting, actually, It is sort of the opposite of what I am trying to do, and that could be closer than people think.

I'm just going to post his now, because usually, "we" end up trying to type fast enough to keep the posts "in order ", and that often causes the posts to "cross" in transmission, and seems pretty "odd" to many of us when we read them!


Thanks again. > barryhc :)

[barryhc]

By CaptiveReef:
The area we are really concerned with is the top layer of the DSB or Plenum, that pint of water can be constantly moved from the water column to the top of the bed at a rapid rate,( the normal flow a powerhead would create), but it's the rate it goes through the bed, a 5 second draw through the bed would destroy the environment for the bacteria, the 8 hours after would not even matter with that pint of water. There has to be natural diffusion in the bed up to that eggcrate level, then a 5 second draw can be made without effecting the upper levels.

Why is it the "top layer" that we are concerned with, and just how deep is this top layer?

The 5 second "draw" is a "sub function" of "draw depth". It is not the important factor here.

The "draw depth" is the important factor, at least in my opinion, and it is of course, only an opinion, but we could make the "duration" of the "draw" 1/2 second if you like, or 30 seconds, but it is the depth of this draw, that will most affect the bacteria.

"Draw depth" is the distance you "pull" water down into the substrate each time you "draw" through the plenum.

If this "depth" is that crucial, we could reduce that depth to, say, 1/32" each time.

You are headed in a slightly different direction here, than I am,
and I don't have any problem with that, but I don't think the bacteria really care.

If the bacteria population is going to be destroyed by drawing water into the substrate 1/8 " at a time, then I would like to hear some explanation as to why, or how, that is so.

I'm not even disputing it, yet.

Thanks again, > barryhc :)

[barryhc]

By "haid":
Yes, Anaerobic is what I meant. Sorry not always great with terminology. I would think this method would allow you to keep the top layers from going anaerobic(pushing water up and through from the column), reduce the load on the sandbed to begin with, with less large particles there to break down. The phosphate should migrate most of the time to the bottom plenum and be wasted in a slow continuous manner. In effect draining water for small but continuous water changes.

Well, I agree with most of this actually, if I'm reading it right.

I don't think though, that we have any concern, or problem, so much, with the "upper level" ( or layer ) "going Anaerobic", but how deep, or thick, is this "upper layer" anyway?

Especially, if "we" are "forcing" water to flow down into the substrate very often, for very "short distances"? This will keep the "upper layer" Aerobic, right?

I do not believe that this would over "oxygenate" the "depths" of a 6"- 8" deep substrate. This would be at the rate of about 5/16" of downflow, per day. It would take 20 days for this water to reach the top of the plenum. This rate, is going to destroy the bacteria?

I am actually looking for "critters", crabs in particular, to keep the surface of the substrate rather clean, and high flow, as well, to keep this "stuff" in "suspension", for removal by skimming etc..

Substrate in the 1-2mm range will "reject" a very large portion of any detritus that "wants" to collect at the surface, and crabs, and high flow, would get "it" into the water column.

This portion of the detritus control consideration is working very well, in my tank, and has been for more than 7 mos.. I know that isn't all that long, but I would have noticed a detritus problem by now, wouldn't I?

Anything "continous" has a lot of associated "flow balancing" problems, if the flow is going to be "wasted".

Let me know what you think here "haid", and Thanks. > barryhc :)

[CaptiveReef]

Originally posted by barryhc
By CaptiveReef:


Why is it the "top layer" that we are concerned with, and just how deep is this top layer?

The 5 second "draw" is a "sub function" of "draw depth". It is not the important factor here.

The "draw depth" is the important factor, at least in my opinion, and it is of course, only an opinion, but we could make the "duration" of the "draw" 1/2 second if you like, or 30 seconds, but it is the depth of this draw, that will most affect the bacteria.

"Draw depth" is the distance you "pull" water down into the substrate each time you "draw" through the plenum.

If this "depth" is that crucial, we could reduce that depth to, say, 1/32" each time.

You are headed in a slightly different direction here, than I am,
and I don't have any problem with that, but I don't think the bacteria really care.

If the bacteria population is going to be destroyed by drawing water into the substrate 1/8 " at a time, then I would like to hear some explanation as to why, or how, that is so.

I'm not even disputing it, yet.

Thanks again, > barryhc :)
In this theory the upper layer of substrate is the deeper portion of this bed. The bottom layer is sharing space with the manifold most of the draw point will be around the manifold and just above it. With the 5 second draw these low area's will be only affected, the upper depth of the bed will not be affected so oxygen will not be pulled into the bed.
This way diffusion will be performed naturally in the upper bed, and the waste that has been diffused down to the manifold area can be drawn out.
You are looking to manually draw the water 1/8 inch at a time through the bed, you would have to draw the water from an uplift tube, like you said a pint at a time every 8 hours.
The only problem I see with this is 8hrs enough time for the bacteria to break down the Nitrate into Nitrogen before the next draw.
You are going to have to build a prototype and try it, if you have a rise in Nitrates then the process is compromising the DSB.


:D CaptiveReef

[kbmdale]

so basically Now we have come to the conclusion that there are 3 layers in the substrate we should be concerned with. The upper aerobic, the middle anoxic, and the bottom anaerobic....

So If we draw to much we would effectively hender the anoxic because it would be the first area to be introduced to 02....Well there is another variable to be considered.

All three layers are important correct? Is there any reading of info on the precise function and what is broken down in these three layers?

[barryhc]

By CaptiveReef:
In this theory the upper layer of substrate is the deeper portion of this bed. The bottom layer is sharing space with the manifold most of the draw point will be around the manifold and just above it. With the 5 second draw these low area's will be only affected, the upper depth of the bed will not be affected so oxygen will not be pulled into the bed.
This way diffusion will be performed naturally in the upper bed, and the waste that has been diffused down to the manifold area can be drawn out.

>>Well, "kinda-sorta", I guess. I can't tell if this is your theory, or my theory. It sounds like a combination of both to me. <bhc>

By CaptiveReef:

You are looking to manually draw the water 1/8 inch at a time through the bed, you would have to draw the water from an uplift tube, like you said a pint at a time every 8 hours.

>>Yes.

By CaptiveReef:
The only problem I see with this is 8hrs enough time for the bacteria to break down the Nitrate into Nitrogen before the next draw.

>>H-m-m-m, If we "draw down" the "entire water column" by .001", and do this 375 times a day, once every 3.8 minutes, then we will move the "entire water column" down by .375" a day. > 3/8" right?

This is going to cause an "oxygen gradiation" to occur within "the entire depth of the substrate". right?

This is going to mean Aerobic conditions at the surface of the substrate, and then "gradually" reducing amounts if oxygen is "we" go deeper into the substrate. right?

The Aerobic area in the substrate will extend farther down into the substrate than it does in "conventional" DSBs or Plenums. I'm not sure how far.

The Anoxic area in the substrate ( which is particularly "thin" in DSBs ) will become stretched ( thicker ), and also extend farther down into the substrate than it does in "conventional" DSBs. Again I'm not sure how much ( thickness ), or how far ( depth ).

The Anaerobic area in the substrate will of course come now, below the Anoxic area, and will extend down to the glass.

This represents an "oxygen gradient" in the substrate

It is my intention to have the plenum "drawing" small volumes of water from this Anaerobic area at the bottom very frequently. That is however frequently is necessary to avoid causing any "undue harm" to the bacteria populations.

If "we" had an oxygen probe at 2" or 3" inches above the plenum, I predict that very, "VERY" little fluctuation in the oxygen "level" would be noted.
< bhc >

By CaptiveReef:

You are going to have to build a prototype and try it, if you have a rise in Nitrates then the process is compromising the DSB.

I installed the prototype 4 mos. ago, and I have not started wasting yet. My Nitrates are < 1ppm currently. When I ( or anyone else ) start "wasting", I think several components in the effluent should be checked.

Oxygen for one, of course!

Phosphate as well, I think.

Nitrates? I think I'll just keep an eye on the tank water, like you say.

I hope this clears things up a "tad bit". I'm just trying to help.

Now about diffusion. Just what does "diffusion" mean anyway? Any thoughts on this, by anyone?

Thanks, Captive reef, and "all"! > barryhc :)

[barryhc]

Kris, You posted while I was typing my reply. It's hilarious sometimes, isn't it?

I agree with you post immediately above! > barryhc :)

[kbmdale]

As far as importance and proccess,

I think the top layers have the greatest job doing the nitrification

the byproduct of that is proccessed further in the second axonic layer

then anything left over is proccessed and stored in the bottom (sink)...

If this is correct, we should be able to move anything we want out of the sink without hendering the tanks biological filtration being doen in the SUBSTRATE....TRUE

If we remove the "sinks" collection of byproducts to fast we will force the 2 areas above to loose effieciece by shrinking the axonic area. If we remove it to slow, we will still allow for a build up which in itself will reduce the anoxic area by having the anaerbic area grow in that way....


MAN we really really have to find the right equation for "waste amount" "Pull duration"....If its wrong we could just be making things worse...


I'm not being Negative, But I am just now seeing the area that will be effected by to little or to much pull, and the bacteria in that area would be the first to suffer. If there were a way to monitor that axonic area of the bed this puppy could be dialed in to perfection....AGREED?????? or am I Just a nutty guy running on to little sleep...:lol:

[barryhc]

So, exactly Kris, let's find some of that reading. Randy Holmes Farley, might have some, Eric Borneman R. Shimek maybe, and many others.

The above three might be more toward DSBs, and that's perfectly fine. We needn't endorse "everything" that anybody else says in "it's entirety", either, but reading is good!

This is where I've been trying to go for 3 pages now, I'm very patient.

There is going to be an "oxygen gradation" in the particular system that I am "currently" promoting, and for that system, we have to allow that "bacterial process depths", are not going to coincide exactly with any published information.

In fact, for my case, I don't want them to "conform", I wan't to improve them. Particle size, bed depth, "draw depth and frequency . . . there I go again! :lol:

Let,s find some of this good reading, and maybe define "diffusion" while we're at it.

Thanks again Kris! > barryhc :)

[barryhc]

We're "passing in the night again" Kris. Right again!

E X A C T A M U N D O !!!!!!!!!

> barryhc :)

[barryhc]

Kris, I believe that the Anoxic zone is going to stretch ( get thicker ), and the anaerobic zone will become "somewhat thinner".

"We" need to cause the thickness of the anaerobic zone, to become thinner, but not "gone", thus maintaining, and actually "improving" the thickness of the Anoxic zone. I have been trying to get anyone in the world to understand this for over three mos. now.

It seems like you do! and Thanks again! > barryhc :)

[kbmdale]

Well I understand that:) I think thats working in a posative way... As long as that axonic area doesn't shrink I don't think the bacteria will be hindered.

So by it growing downward (baby steps) it should make for more effeiciency...RIGHT ON BARRY


:)

[barryhc]

We just love that anoxic zone don't we? Let' stretch it a "bit".

Actually when you find some reading on this, "Many" will say that the Anoxic zone only exists for maybe as little as .5mm in a DSB.
I can't say that "it's" true, but you will read it!

You may also read, that the Aerobic zone, exists for only 10mm or so, that would be without the help of "critters" of course, and almost nobody does that, and "cukes", "Nasarrius snails", etc.. will very significantly effect this "depth".

"Depth", I say? What depth ? Diffusion depth? Just what is "diffusion" anyway? Ever hear of "advection"? "Goemans and Gamble" talk abou it, and I under stand it, but I don't ever see it in common use.

Advection depth for us here, is that depth of "pore-water"
flow, that occurs as a function of the flow in the water column.
That would be for us, not from wasting, or bacteria, or from critters, just from water column flow interacting with the particle size in the substrate.

Almost no advection occurs in a "sand bed" ( like typical DSB ) because of the grain size. Some advection occurs in "standard plenums" because of the larger particle size, 2-4mm is common.

So, what is "diffusion"? Thanks > barryhc :)

[kbmdale]

During his MACNA XVI presentation, Julian Sprung discussed his research into the physical effects of water motion on the biological filtration capacity of sediment beds in aquaria. The basic conclusion from that work (covered in more detail in Delbeek, Sprung, In press) is that the location and volume of rock as well as the surface shape of the sand or gravel (e.g., mounds, sloped, or flat) can dramatically affect the efficiency of water flow, oxygen diffusion and nutrient processing in the sandbed. The results we present here likewise argue that there are complex interactions between sandbed depth, particle size and flow that are sometimes counter-intuitive. Obviously, additional research along these lines may prove very fruitful to our ultimate understanding of biological filtration in recirculating aquaria.

http://www.advancedaquarist.com/2005/7/aafeature

I can't answer about diffusion YET...But this article has some really good studies on the sediment size, water flow, and depths....Could be a very useful as far as getting a few numbers and size to rate ratios...:)

NOw I'm on to diffuse diffusion...

I'll be back later after a doctor visit...

[barryhc]

I heard a couple months ago, that Julian was going to present some information that sounded like what I was looking for.

I didn't know that it had become available.

I'm off to read, but I will still be here. Thanks > barryhc :)

[barryhc]

Kris, I did a very quick "skim" on the link that you gave me, and I think I'm already up to date on that.

I don't think that "they" are playing around with "wasting" yet, so "we" have to be careful what we read into any conclusion that "they" come to.

I think it will remain an "important read", let's just be careful about our own conclusions. I like the fact that they are going to include more animals now, I happen to be generally in favor of them, and it is the "whole system", that works or not including "blah- blah-blah" I won't start on that again right now!

Thanks > barryhc :)

[barryhc]

I think another very important "read" for us here is the "BRP" thread I mentioned previously. All kinds of information there regarding Aerobic to Anaerobic and back again, and how this is being used to process Phosphate primarily.

It may not seem to represent what were trying to do here, but, if the downward flow was 5/8" every other day, what would be happening to the bacteria? I'm not promoting anything like this "currently", but it is educational just the same, regarding "draw depth" and "frequency", heh?

I haven't yet found anything else that seems to be "real close" for us. Actually, I think "we" are the ones who are on the leading edge of this! That "we", is "everyone" who is posting in this thread!

Thanks all. > barryhc :)

ooPS! another "ringy-dingy" 4 seconds ago! :lol:

[CaptiveReef]

Well I'll try to tackle the ol diffusion discussion without making a fool out of myself, (I hope).
As we know diffusion occurs in the DSB where the perfect conditions are present to create an anoxic zone.
The actual diffusion is when the bacteria in the anoxic zone use the NO3 to breathe they strip away the oxygen molecule and leave one Nitrogen atom to bubble up as Nitrogen gas. The process of the slow release of Nitrogen bubbles and the introduction of new water into the bed when the Nitrogen is released is the diffusion process.
Hope I got this one?

:D CaptiveReef

[kbmdale]

I think your right on captive. Thats what I am finding in my search for he answer. So would creating a bigger anoxic area for diffusion be benifitial to the tank?

[barryhc]

Now that "we've made it to this point, I think that some "layering of the substrate is going to be quite valuable for various reasons.

No, we don't often find it in "the wild" that way. I keep my tank in my "Diver's Den", not . . .

We don't have "wasting plenums" in the wild do we?

Ok, I just couldn't help it, and I'm only referring to the "High Frequency" type of plenum here, that I have been promoting. There may end up being several types of successful "systems" that come out of this investigation, and I certainly hope that is the case!

Just the same, I'm referring in this particular "post" to layering of the substrate that might be conducive to the overall performance and longevity of a "High Frequency Wasting" type of plenum.

Ok, let's start with typical ( or standard ) type of plenum according to "Goemans", and start from there.

Let's try to pull from the center of the tank as much as possible ( details upon request ).

Let's also cram in as many feeder tubes as possible and use lots of rather small holes to "balance flow" across the substrate area.
Calculate these hole requirements to match the flow, don't guess please.

Put in the egg crate and screen just like the "Goemans" model. OOPS!!!! . . . WHOA THERE, HEH?

"Screen", is not very descriptive, and probably works fine in a "Goemans" style plenum, but this "might" deserve some consideration. I have screen on my plenum, and I'm not too worried about it. Mine has about 1.5mm ( or 1/16" ) holes in it.

Now here is where I may "throw" some people off, but I'll take it slow.

Let' start with the larger particles at the bottom, right on top of the screen. How about 3-5mm. That is not "sand", that is gravel. Let's use nicely grade stuff here and rinse it thorughly first .

Why, you ask, I'll get to that later. Let's just keep looking at this "model" for a few more steps here , Ok? Well, alright, I don't want anything to cause blockage around the plenum, you see.

1/2 " deep of this gravel should probably suffice from a "flow" standpoint. "But what about the anaerobic bacteria", you say, yeah, they'll be there, what about them?

Ok, how about, say, 1"depth of 2-4mm gravel above that? What's that for, you might ask? Well, . . . "Goemans" uses up to 4" depth of this stuff, so are you asking if it is too much, or too little?

The "hope" here is, that there is a lot of Anoxic activity in this "level" of the substrate. How thick is this Anoxic zone anyway, that everyone seems to know so much about? Remember the .5mm thickness of "Anoxic zone" mentioned previously in regard to DSB's?

All right, so here is where get to start "playing with it".

Now the 2-4 mm layer of gravel, is going to block "particle migration" down to about .3mm, that is three tenths of one mm. Don't think so, heh? Try me! Sorry, can't help it on occasion.

If you want to go with particles smaller than that, you may want to add, yet another layer of .7 to 1.7mm particles, say another 1/2" to 1", whatever.

Let's see now, were at 2" to 2 1/2" deep now right? ( from the "bottom up" )

Well, what do you want to do with it now? That is up to you of course, but for me . . .

Well I,m not going to be having "plugging issues" in the plenum now, because, I'm blocking "particle migration" with the afore-mentioned "larger gravel".

This seems a little bit counterintuitive, doesn't it? That is how I see it working.

Ok, for me, it is now a matter of what "critters", that I ( "we" )want to keep. H-m-m-m . . .

Let's put in a second screen here, to keep the "critters" from messing with our carefully controlled lower layers, heh? I'm thinking 6mm plastic mesh. I'm only trying to stop critters here, nothing else!

I like crabs, and snails, and pods, and cukes maybe, . . . micro stars maybe? Geeze, this is the part that is interesting here, because these animals could have some effect on the the "Oxygen Gradient" in the upper level of the substrate. right?

I think I might try some .7-1.7mm here, but I'm not so sure about how deep. The Gobies might like 3" of this, but that may not suit the "oxygen gradient" I'm looking for.

Oh well, more investigating to do!

What's next? > barryhc


:)

[barryhc]

CaptiveReef, I like your definition of diffusion. Thanks, I'll use that definition now. It sounds like a good one.

Thanks again! > barryhc :)

[CaptiveReef]

Originally posted by kbmdale
I think your right on captive. Thats what I am finding in my search for he answer. So would creating a bigger anoxic area for diffusion be benifitial to the tank?
Yes to make the area bigger it would have to be not deeper, but larger over an area, (square footage) A tank that is greater in depth(front to back) would have a better anoxic area than a tall tank.



:D CaptiveReef

[CaptiveReef]

Originally posted by barryhc
Now that "we've made it to this point, I think that some "layering of the substrate is going to be quite valuable for various reasons.

No, we don't often find it in "the wild" that way. I keep my tank in my "Diver's Den", not . . .

We don't have "wasting plenums" in the wild do we?

Ok, I just couldn't help it, and I'm only referring to the "High Frequency" type of plenum here, that I have been promoting. There may end up being several types of successful "systems" that come out of this investigation, and I certainly hope that is the case!

Just the same, I'm referring in this particular "post" to layering of the substrate that might be conducive to the overall performance and longevity of a "High Frequency Wasting" type of plenum.

Ok, let's start with typical ( or standard ) type of plenum according to "Goemans", and start from there.

Let's try to pull from the center of the tank as much as possible ( details upon request ).

Let's also cram in as many feeder tubes as possible and use lots of rather small holes to "balance flow" across the substrate area.
Calculate these hole requirements to match the flow, don't guess please.

Put in the egg crate and screen just like the "Goemans" model. OOPS!!!! . . . WHOA THERE, HEH?

"Screen", is not very descriptive, and probably works fine in a "Goemans" style plenum, but this "might" deserve some consideration. I have screen on my plenum, and I'm not too worried about it. Mine has about 1.5mm ( or 1/16" ) holes in it.

Now here is where I may "throw" some people off, but I'll take it slow.

Let' start with the larger particles at the bottom, right on top of the screen. How about 3-5mm. That is not "sand", that is gravel. Let's use nicely grade stuff here and rinse it thorughly first .

Why, you ask, I'll get to that later. Let's just keep looking at this "model" for a few more steps here , Ok? Well, alright, I don't want anything to cause blockage around the plenum, you see.

1/2 " deep of this gravel should probably suffice from a "flow" standpoint. "But what about the anaerobic bacteria", you say, yeah, they'll be there, what about them?

Ok, how about, say, 1"depth of 2-4mm gravel above that? What's that for, you might ask? Well, . . . "Goemans" uses up to 4" depth of this stuff, so are you asking if it is too much, or too little?

The "hope" here is, that there is a lot of Anoxic activity in this "level" of the substrate. How thick is this Anoxic zone anyway, that everyone seems to know so much about? Remember the .5mm thickness of "Anoxic zone" mentioned previously in regard to DSB's?

All right, so here is where get to start "playing with it".

Now the 2-4 mm layer of gravel, is going to block "particle migration" down to about .3mm, that is three tenths of one mm. Don't think so, heh? Try me! Sorry, can't help it on occasion.

If you want to go with particles smaller than that, you may want to add, yet another layer of .7 to 1.7mm particles, say another 1/2" to 1", whatever.

Let's see now, were at 2" to 2 1/2" deep now right? ( from the "bottom up" )

Well, what do you want to do with it now? That is up to you of course, but for me . . .

Well I,m not going to be having "plugging issues" in the plenum now, because, I'm blocking "particle migration" with the afore-mentioned "larger gravel".

This seems a little bit counterintuitive, doesn't it? That is how I see it working.

Ok, for me, it is now a matter of what "critters", that I ( "we" )want to keep. H-m-m-m . . .

Let's put in a second screen here, to keep the "critters" from messing with our carefully controlled lower layers, heh? I'm thinking 6mm plastic mesh. I'm only trying to stop critters here, nothing else!

I like crabs, and snails, and pods, and cukes maybe, . . . micro stars maybe? Geeze, this is the part that is interesting here, because these animals could have some effect on the the "Oxygen Gradient" in the upper level of the substrate. right?

I think I might try some .7-1.7mm here, but I'm not so sure about how deep. The Gobies might like 3" of this, but that may not suit the "oxygen gradient" I'm looking for.

Oh well, more investigating to do!

What's next? > barryhc


:)
I like the progress!!!!! barryhc if I may suggest doing a 2inch bed with the manifold,the screen layer then 4 inches of sand on top.
Just a suggestion, those depths work pretty good for me as a regular DSB.

:D CaptiveReef

[barryhc]

By CaptiveReef:
I like the progress!!!!! barryhc if I may suggest doing a 2inch bed with the manifold,the screen layer then 4 inches of sand on top.

>>Are you still suggesting to "draw" from somewhere in the "mid-level" of the substrate depth? Is that putting the "manifold" above a 2" thick "lower bed", and under a 4" thick "upper bed"?<bhc>

By CaptiveReef:
Just a suggestion, those depths work pretty good for me as a regular DSB.

>> I imagine those depths would work pretty well, for a "regular DSB".

Did you catch the part about "particle migration" and not "plugging up" the plenum?

Just checking. > barryhc :)

[haid]

Another off the wall option to just throw out there I was thinking about is creating a false anoxic layer. We should easily be able to blow out the aerobic layer on top(reverse undergravel). So that gets us to Nitrate and left over phosphate, ect. What I was thinking is create the plenum base with not sand but a partition(glass, acyrlic). With the Aerobic section/liverock puting nitrate back to the system water along with unbroken down detritus. Ok now the plenum is kept oxygen difecient with the use of the partition and a slow draw from the plenum. Ok so you barry coils of tubing in the top aerobic layer and hook them to small bulkheads through the partition. The slow draw from the plenum will cause new flow to the plenum. The coiled tubing becomes the anoxic layer. Thus Breaking down the nitrate. Phosphate remains but is removed by the continuous wasting from the powerhead mixed plenum. Maybe too complicated to work right. Not sure but I think this could leave a nice "sand bed" for looks on top that will not be "loaded" and could be used by critters. Should eliminate pluging and problems with diffusion rate to the plenum. And a continuous wasting of the "sink". Also the use of wet skimming/good flow to remove what is pushed up and out of the top aerobic layers and to reduce settling on rocks. And also as mention before slow but constant water changes that should not effect oxygen levels in any of the zones and would keep them from shifting to different depths over time. I have a 55 gallon that I am thinking of trying to run simular.

[kbmdale]

Originally posted by CaptiveReef
Yes to make the area bigger it would have to be not deeper, but larger over an area, (square footage) A tank that is greater in depth(front to back) would have a better anoxic area than a tall tank.



:D CaptiveReef

so that brings upmy next point, would a 18-24" wide tank be better than a 12" wide tank for this set-up?

I am also putting together a 16x16x16 cube for a softy tank.

[barryhc]

By Kbmdale:
so that brings upmy next point, would a 18-24" wide tank be better than a 12" wide tank for this set-up?

It depends on the tank "height". The "length" of the tank is unimportant, it is the "width", or dimension from front to back that counts.

Actually, It is the ratio of height to width that gives you a larger surface area, relative to the water volume.

Anyway, the 16 X 16 is a good ratio, lots of area compared to the water volume. It also helps with lighting requirements as well, making T5's a more reasonable posssibility, if you wanted to go that way. I'm not promoting T5's, they just work better in shallower tanks.

Sounds pretty good. Substrate, in the "softy tank? > barryhc :)

[kbmdale]

Undecided on size of substrate yet, THe only guarentee, you won't see any acrylic on the bottom...lol....

[barryhc]

I don't wear pink, and my tank has a glass bottom on it! :lol:

It has some arag. gravel, sand, and CC on it too! :p

I'm going to be using some acrylic for my "fuge". . . Maybe just sand over there though. How deep should it be?

> barryhc :)

[kbmdale]

The best fuge I ever ran was built like this

http://i2.photobucket.com/albums/y40/kbmdale/Untitled-1.jpg


8" sand bed
water goes in and dropps any detritus it might bring with it in the left chamber, then moves swiftly across the top of the sand and over into the return chamber. You can vacuum the first and last chambers and be detritus free,

[barryhc]

So Kris, did you "catch" any of that stuff about "particle migration", "plenum clogging", Anoxic and Anaerobic bacteria populations in the "lower level" of substrate?

Maybe were back to the mechanical portion, of the "flow design". Your original diagram was actually pretty good, LOTS of holes there. Gotta consider "flow restriction" here, we actually WANT some flow restriction based on the "total area" of these holes, in order to maintain fairly even "flow balancing".

Good luck with the "softy tank", > barryhc :)

[barryhc]

Kris, did you keep any algae, Micro, or Macro in that refugium design?

> barryhc :)

[kbmdale]

Originally posted by barryhc
Kris, did you keep any algae, Micro, or Macro in that refugium design?

> barryhc :)

Nope I had a seperate aglae grow out tank. I found the macro liked higher flow than my DSB could process... Th fuge above only had about 150 gph rolling through it, seems the DSB needed the slower flow to filter the water. MY macro's loved 600-800 gph tubling them.... But this was way off the topic so back to the lecture at hand :)

[kbmdale]

[QUOTE]Originally posted by barryhc
So Kris, did you "catch" any of that stuff about "particle migration", "plenum clogging", Anoxic and Anaerobic bacteria populations in the "lower level" of substrate?

Got it...or a good enough understanding of what we need it to do.

Maybe were back to the mechanical portion, of the "flow design". Your original diagram was actually pretty good, LOTS of holes there. Gotta consider "flow restriction" here, we actually WANT some flow restriction based on the "total area" of these holes, in order to maintain fairly even "flow balancing".

Yep this is the step I see next. We need an even pull manifold that allso has a backward bump for time to time to unclogg.

[barryhc]

I guess you're right. :lol: I have to run, Enjoy! > barryhc :)

[barryhc]

EXACTAMUNDO!! BYE! > tomorrow > barryhc :)

[kbmdale]

chech your PM

[CaptiveReef]

Originally posted by barryhc
By CaptiveReef:


>>Are you still suggesting to "draw" from somewhere in the "mid-level" of the substrate depth? Is that putting the "manifold" above a 2" thick "lower bed", and under a 4" thick "upper bed"?<bhc>

By CaptiveReef:


>> I imagine those depths would work pretty well, for a "regular DSB".

Did you catch the part about "particle migration" and not "plugging up" the plenum?

Just checking. > barryhc :)
Yes I got the part about particle migration, I have been thinking about the manifold placement with both setups.
What I'm suggesting is have the manifold in the 2'' bed on the bottom with a DSB setup, and have the manifold in the empty Plenum space with the Plenum setup. I feel with the Plenum setup, it would function alot better due to the manifold is open and it would be a better draw. Also with the Plenum application you may be able to get a longer draw because it is at the very bottom of the bed, which would make a better draw on the lower zone of the bed.




:D CaptiveReef

[voodoody]

I guess I don't understand the concern with flushing the anoxic and anaerobic layers with "clean oxygenated water". Understand that oxygen is not toxic to anaerobic bacteria, these bacteria simply do not require oxygen for their metabolic processess. The anaerobic bacteria will exist on a biofilm. It would be highly unlikely that their populations would decline with an intermittant fast flush. The oxygen would likely be consumed quickly via diffusion into the upper bed and the anaerobes would soon be functioning as usual. I do agree that if this was done on a continual basis with large volumes, the bacterial flora of the deeper layers could be changed. This, however, is not required to flush the lower layer nutrient sink periodically.

[CaptiveReef]

Originally posted by voodoody
I guess I don't understand the concern with flushing the anoxic and anaerobic layers with "clean oxygenated water". Understand that oxygen is not toxic to anaerobic bacteria, these bacteria simply do not require oxygen for their metabolic processess. The anaerobic bacteria will exist on a biofilm. It would be highly unlikely that their populations would decline with an intermittant fast flush. The oxygen would likely be consumed quickly via diffusion into the upper bed and the anaerobes would soon be functioning as usual. I do agree that if this was done on a continual basis with large volumes, the bacterial flora of the deeper layers could be changed. This, however, is not required to flush the lower layer nutrient sink periodically.

If you introduce oxygenated water into the bed, you will remove any Nitrate, which is a usable source for the bacteria. They use the Nitrate to breathe. Also the environment that is created in the bed in which these bacteria need to perform their function will be disrupted, and the end product will be Nitrate levels spiking.
In this discussion we are trying to do small timed draws of water to remove waste that has diffused to the bottom of the DSB bed or Plenum, without introducing oxygenated water into the bed in the same process.

:D CaptiveReef

[salty joe]

This thread is very interesting.

I have also been kicking around the idea of regularly draining a sand bed. What I am considering is a deep sand bed with a plenum underneath. I would have a single drain in the bottom of the tank. I would probably place a layer of window screen about an inch or so from the bottom of the sand to prevent animals from digging clear to the plenum in an effort to minimize channeling. At the drain I would place a one-inch shutoff valve (top valve). From there I would run a pipe straight to the floor, and with 2 90° elbows turn the pipe straight up so that it was higher than the highest point in my aquarium. At the bottom of this U tube, I would place another shutoff valve. To drain the plenum, I would make sure the bottom valve is closed and open the top valve. The water in the U tube would then reach the same level as the water in the aquarium. Then, I would close the top valve and open the bottom valve to empty the U tube. This way, the amount that I remove would be consistent each time. I could construct the U tube from different sizes of PVC to adjust how much water I remove. No moving parts to fail.

I would monitor the phosphate in the water that is exported from the plenum. In my opinion, the system would be dialed in when the phosphate level in the exported water is steady week after week and the tank is doing well. To me, this would indicate a balance has been struck between how much phosphate is going into the sand bed and how much phosphate is being exported from the sand bed. Incidentally, I also think that perhaps phosphate measurement from the plenum water would be an indirect measurement of other undesirable things like metals and who knows what else.

With this system, I wouldn't care if it took five minutes or five hours to fill the U tube. I am also not too terribly concerned about channeling. As long as phosphate exports were consistent, and the aquarium was doing well, I would feel comfortable.

The one thing that I am not sure about is what kind of membrane should I use for the very bottom of the sand bed to keep the very fine sand out of the plenum?

Just my thoughts on the matter. I look forward to watching this thread grow.

Joe

[barryhc]

By voodoody:
I guess I don't understand the concern with flushing the anoxic and anaerobic layers with "clean oxygenated water". Understand that oxygen is not toxic to anaerobic bacteria, these bacteria simply do not require oxygen for their metabolic processess. The anaerobic bacteria will exist on a biofilm. It would be highly unlikely that their populations would decline with an intermittant fast flush.

>>This information could be helpful, It is the kind of information that I have been looking for. Please give links, or otherwise, to "back it up". and Thanks! <bhc>

My take on it, (without "better information" ) is that Anaerobic bacteria "predominate" in an Anaerobic area. "They" either" migrate or develop there. They "like it there". They have food there and they are alive there. If a "significant"change in the oxygen level occurs there, other bacteria that like the new level of oxygen, will migrate there. Now we have fostered some competition in this area between bacteria colonies. Is this good or bad? <bhc>

By voodoody:
The oxygen would likely be consumed quickly via diffusion into the upper bed and the anaerobes would soon be functioning as usual. I do agree that if this was done on a continual basis with large volumes, the bacterial flora of the deeper layers could be changed. This, however, is not required to flush the lower layer nutrient sink periodically.

>>There's that "diffusion" word again. I thought "we" agreed, that diffusion had to do with downward motion, that occurs as a direct result of nitrogen gas bubbling up, and therefore pulling water downward. "Oxygen consumed via diffusion"?

Shall "we" define "diffusion again? > CaptiveReefs' department.

"Flush HOW MUCH"? Say, 2" of "water column"? 1/4"? <bhc>

Nice post, and welcome "voodoody", I'm just asking questions. > barryhc :)

[voodoody]

Oxygen will be consumed by aerobic bacteria in the upper sand bed. As this happens, oxygen will diffuse from the flushed lower sand bed to the upper bed. The rate of diffusion is the only variable. If the diffusion takes an eternity, it might allow for replacement of the bacterial flora with an aerobic species until the oxygen is used again. I do not have anything to back it up, however, it is intuitive that the rate of diffusion of a gas to the upper sand bed will be quicker than the downward repopulation/replacement of anaerobes by aerobes in the lower sand bed. Again, this might be different if oxygen were actually toxic to anaerobes, however, it is not. I have a plenum in my DSB modeled after ldrhawke with some variations. I did use a "packed grid" with very small holes to prevent "short circuiting". I used the same substrate. I did not use a fabric barrier as he did as I felt it would trap the sand critters.

I wouldn't hesitate to flush any volume of water through the bed. I think you could flush an equivalent volume of the whole sand bed or more and within a few days, the anaerobic zones will be functional. I have no "proof" of this yet, but I do have an understanding of how bacterial flora survives even short term antibiotic therapy if a biofilm has been established. My tank has only been set up for 3-4 months, however, and I have not flushed yet as I do not think significant nutrient loads are present. I did flush several times before placement of the bed to verify the function and speed of the flushing action. It is amazing how fast water can drain through numerous tiny holes.

[barryhc]

By CaptiveReef:
Well I'll try to tackle the ol diffusion discussion without making a fool out of myself, (I hope). As we know diffusion occurs in the DSB where the perfect conditions are present to create an anoxic zone. The actual diffusion is when the bacteria in the anoxic zone use the NO3 to breathe they strip away the oxygen molecule and leave one Nitrogen atom to bubble up as Nitrogen gas. The process of the slow release of Nitrogen bubbles and the introduction of new water into the bed when the Nitrogen is released is the diffusion process.
Hope I got this one?

>>CaptiveReefs' definition of diffusion was accepted as stated, and I still accept it.

Still, after the Anoxic bacteria strip the oxygen molocule from NO3, and then bubble up Nitrogen gas, what is left from that process, besides the bacteria? No dispute here, but do you have a link for this? I love to read.<bhc>

By CaptiveReef:
If you introduce oxygenated water into the bed, you will remove any Nitrate, which is a usable source for the bacteria. They use the Nitrate to breathe. Also the environment that is created in the bed in which these bacteria need to perform their function will be disrupted, and the end product will be Nitrate levels spiking.

>>OK, I'm getting confused here, and I rarely get confused.

I thought we wanted to remove the Nitrate in the Anoxic zone, and so, if "we" add oxygen, we will "remove the Nitrate"?, and we are going to get a "Nitrate spike"?

Help!! where's that "reading" on this, now my head hurts too!

Thanks again, >"reading, links" > barryhc :)

[barryhc]

Nice post, voodoody, were in the same ball park here obviously. We are passing replies simeltaneously, which is becoming common in this thread. I'm still conisdering the info. in your "last" post. <I do not think significant nutrient loads are present.> I will be reading it more thoroughly "right now".

"We" will both get the opportunity to start "wasting" soon. Can you tell me more about your "substrate", and any layering at all. Also, what size tank, and what are your objectives "animal wise".

Other important "equipment" on your system?

Thanks again, very much! > barryhc :)

[voodoody]

Tank size is 190 gallons low iron glass + Redmond Reef refugium with chaeto + Euroreef protein skimmer (CS-8 series). I used the CaribSea Special Grade Reef Sand. Closed loop is a Sequence Dart with four outputs. Two outputs are Sea Swirls for turbulance. Two 250w metal halide DE (10k) and one 175w DE(20k). This will be mixed reef when fully stocked with soft and sps, clams and a few fish (species undecided at this point).

[barryhc]

We might have to revise the "diffusion" definition if anyone is interested. I have seen "diffusion" . . . "flashed around" like a "big gold ring" elsewhere. I am just here to learn, and understand.

By the way voodoody, LDRHawkes plenum design was "pretty close" to begin with ,as I see it. The "goemans" style screen and eggcrate looks better to me. ( sounds like what you're using ) "Feeder tube cramming" looks good as well.

I like to pull from the center of the manifold when possible, but it is not a prerequisite of course.

It sounds like your "draining by gravity", and I'm intersted in your "test flushes" there.

Thanks again! > barryhc :)

[barryhc]

See us "passing in the night" again? Magnificent set-up by the way, I haven't gotten that far yet. I'm still "playing with my "little hex" plus "fuge. I'm preparing here, for a 200 gal. probably for installation around christmas. your set-up sounds exceedingly similar to where I'm headed with the "big one".

Thanks again! > barryhc :)

[barryhc]

Saltyjoe, I would be a little more concerned with channeling, if I were you, but then I'm not. However, I particularly like your "U tube" idea.

I like the part about varying the "collection" portion of the "gizmo" to control "draw volume".

I still like "Short burst" "High flow" for avoiding channeling, but heh, I just can't help it, I guess.

In any case, I think your right on, about checking for phosphate, and whatever else you're interested in.

Welcome to the thread! > barryhc :)

[CaptiveReef]

Originally posted by barryhc
By CaptiveReef:


>>CaptiveReefs' definition of diffusion was accepted as stated, and I still accept it.

Still, after the Anoxic bacteria strip the oxygen molocule from NO3, and then bubble up Nitrogen gas, what is left from that process, besides the bacteria? No dispute here, but do you have a link for this? I love to read.<bhc>

By CaptiveReef:


>>OK, I'm getting confused here, and I rarely get confused.

I thought we wanted to remove the Nitrate in the Anoxic zone, and so, if "we" add oxygen, we will "remove the Nitrate"?, and we are going to get a "Nitrate spike"?

Help!! where's that "reading" on this, now my head hurts too!

Thanks again, >"reading, links" > barryhc :)

Okay let me explain, the Nitrate laden water is pulled downward into the bed by gravity, diffusion,(Nitrogen bubbles up, for every bubble new Nitrate laden water takes it's place in the bed.
If we disrupt the entire bed by allowing new oxygenated water to enter from the top and make it all the way to the bottom , it will change the entire environment that the bacteria need to perform there job. There will be no stripping of oxygen from the NO3 molecule. The entire process/environment will be compromised, now that this has happened the bed's ability to diffuse Nitrate has been changed and Nitrate levels will start to increase,(spike) until the bed is able to return back to it's original state/ proper environment to support the bacteria.
Remember we have to keep the bed pretty much oxygen free so the bacteria will continue to use the NO3 for their oxygen source.
As soon as the bed receives additional oxygen this stripping of the NO3 molecule stops.
That is the reason for small controlled draws from the bottom of the bed,to remove waste, but not pull the water all the way down into the bed. IMO I would only allow the 1st inch of the upper bed to be allowed to receive any introduced oxygenated water.

:D CaptiveReef

[voodoody]

Egg crate will allow "short circuiting" according to ldrhawke. I think he is right. I modified his manifold. Mine consists of two "grids" with pvc running both vertically and horizontally rather than just horizontally. These are both connected to a center manifold. I took digital photos before it was covered with substrate, however, I am having a hard time locating.

The concept that flushing will remove nitrate and the bacteria will starve and therefore will not be able to convert newly formed nitrate and one will see a nitrate spike does not make sense in my humble opinion. Bacteria do not die off from a short term lack of nutrients. They will be able to process them as soon as they become available again.

[barryhc]

Voodoo and Captive both: I have an open mind entirely on the oxygenation issue. Actually, I'm more concerned than voodoody, and less concerned than CaptiveReef, so I'm just going to keep "following" on this. Thank you both!

By voodoody:
Egg crate will allow "short circuiting" according to ldrhawke. I think he is right.

>>This part I don't quite follow, but maybe.

"Short circuiting" in the plenum, based on "channeling", in the substrate above?

If so, this is my reason for the lower level "gravel" layer, up to 2"-3" deep, and then 6mm plastic screen "critter barrier". However, maybe I see your point. voodoody, could you elaborate? I'm listening very carefully. Thanks again > barryhc :)

[voodoody]

Exactly. Short circuiting based on chanelling. The flow will take the path of least resistance. The idea of numerous tiny holes rather than egg crate is to make it less likely that some zones that will receive no flow due to uneven clumping / consistency within the substrate. This had not occurred to me, but I do think that ldrhawke knew what he was talking about hear. A detailed discussion of this in the prior thread was quite convincing to me.

[barryhc]

Originally posted by CaptiveReef

Remember we have to keep the bed pretty much oxygen free so the bacteria will continue to use the NO3 for their oxygen source.
As soon as the bed receives additional oxygen this stripping of the NO3 molecule stops..

Maybe we're getting somewhere here, but the "upper portion" of the bed needs to remain Aerobic in order to produce the NO3 in the first place, Right? ( unless you're favoring bio-balls, which I'm not )

Then the Anoxic portion of "the bed" which is "under" this "Upper Aerobic portion, can perform the "work" that you describe. Am I still confused?

Originally posted by CaptiveReef

That is the reason for small controlled draws from the bottom of the bed,to remove waste, but not pull the water all the way down into the bed. IMO I would only allow the 1st inch of the upper bed to be allowed to receive any introduced oxygenated water.

Or less possibly, I don't know for sure about any magic number for Aerobic zone depth, I'm still looking for information, and I still believe that the zone depths will be other than published information if "simulated continuous flow" is performed on the substrate. > "oxygen gradation"

I'm still particularly interested in the Phosphate processing, that I seem to understand, is occuring in the "lower Ph" Anoxic and anaerobic portions of "the bed".

Any thoughts here?

Thanks again, this is progress. > barryhc :)

[voodoody]

Unlike ammonia which can ultimately be converted to gas which bubbles off, phospates can only be incorporated into the bacteria. Ultimately the DSB acts as a sink for phosphates, sulfur containing compounds and heavy metals. This is thought what acts to ultimately cause DSB's to crash. The sink gets full and starts to leak nutrients back into the water column. This is why I think a refugium is important. Harvesting macroalgae can actually eliminate or export this out of the water column.

[barryhc]

Originally posted by voodoody
Exactly. Short circuiting based on chanelling. The flow will take the path of least resistance. The idea of numerous tiny holes rather than egg crate is to make it less likely that some zones that will receive no flow due to uneven clumping / consistency within the substrate. This had not occurred to me, but I do think that ldrhawke knew what he was talking about hear. A detailed discussion of this in the prior thread was quite convincing to me.

Where are these "numerous tiny holes", and then, why "rather"than" egg crate.

I have 72 .040" dia. in the "plenum manifold", and egg crate with screen over that, then the gravel over that avoids both "clumping" and "particle migration" as well, as I have
explained at some considerable length.

I have not even seen the previous link here. I saw the basic explanation that LDRHawke made, through a link about 5 mos. ago., which was one "post" including pictures. and nicely done.

I have asked LDRHawke directly, and specificly for his opinions, and he has not responded.

Thanks again > barryhc :)

[barryhc]

Originally posted by voodoody
Unlike ammonia which can ultimately be converted to gas which bubbles off, phospates can only be incorporated into the bacteria. Ultimately the DSB acts as a sink for phosphates, sulfur containing compounds and heavy metals. This is thought what acts to ultimately cause DSB's to crash. The sink gets full and starts to leak nutrients back into the water column. This is why I think a refugium is important. Harvesting macroalgae can actually eliminate or export this out of the water column.

This is exactly how I understand it. I said the system I'm looking at installing is almost identical to yours.

I will build my own refugium, my own "lighting hood" and or whatever we want to call that, and possibly my own skimmer.

However, beyond that the only other difference between our systems, may be that I want to include Gobies, and possibly Jawfish, which you have not yet specified.

I may even include a "Gobies garden" portion of substrate management in 1/4 or less of the tanks "substrte area" as well, in order to avoid some portion of the "channeling problem" that "they" would tend to promote with their "burrowing Habits".

Wasting a plenum can "export" some of this Phosphate, sulfur, and metals "sink" can't it? Maybe even avoid a "crash"?

How are we doing? > barryhc :)

[barryhc]

Voodoody, can you give us some information on your "drain by gravity" test flushes, that you conducted shortly after installation? I'm particularly interested.

How are we doing on "refugiums" and "sink wasting"?

Thanks again, you are helping a lot, and it is appreciated!

> barryhc :)

[barryhc]

Originally posted by barryhc
Wasting a plenum can "export" some of this Phosphate, sulfur, and metals "sink" can't it? Maybe even avoid a "crash"?


This is why I pursued "plenum wasting" in the first place, about 8 mos. ago.

"Plenum wasting" was actually "in Vogue" about 6 years ago actually, and "everyone" gave up on it, as far as I know.

LDRHawke decided to try it again, and was highly satisfied for "a time", and then he gave up on it too, as well. If that's not so, he is welcome to explain otherwise.

Where do we go from here?

Thanks to all! > barryhc :)

[barryhc]

So, is it the "substrate" that is the question here? Maybe how "it" affects the bacteria populations, "channeling", "Phosphate binding", "gill damage" for some "critters", any others?

I hope so, that is where I started this thread. I hope that "it" goes wherever else it needs to go, in order to achieve success!

There may be many other considerations as well. Let's "chew on them" some heh?

And let us all continue to enjoy the reef keeping hobby! > barryhc

:)

[salty joe]

Main Entry: dif·fu·sion
Pronunciation: dif-'yü-zh&n
Function: noun
1 : the process whereby particles of liquids, gases, or solids intermingle as the result of their spontaneous movement caused by thermal agitation and in dissolved substances move from a region of higher to one of lower concentration

This is what diffusion has always meant to me.

[barryhc]

That looks like a very good definition SaltyJoe, and it doesn't sound like the "Gold-Ring" type either. Thank you very much.

Originally posted by salty joe
The one thing that I am not sure about is what kind of membrane should I use for the very bottom of the sand bed to keep the very fine sand out of the plenum?
Joe

Membrane?

Did you read about substrate, gravel, plenum, eggcrate, screen, "critter blocking" screen, PARTICLE MIGRATION, etc., earlier in this thread?

Let me know if it remains a question.

Thanks so much for contributing! > barryhc :)

[barryhc]

In case anybody new to the thread missed it.

Originally posted by barryhc
Now that "we've made it to this point, I think that some "layering of the substrate is going to be quite valuable for various reasons.

No, we don't often find it in "the wild" that way. I keep my tank in my "Diver's Den", not . . .

We don't have "wasting plenums" in the wild do we?

Ok, I just couldn't help it, and I'm only referring to the "High Frequency" type of plenum here, that I have been promoting. There may end up being several types of successful "systems" that come out of this investigation, and I certainly hope that is the case!

Just the same, I'm referring in this particular "post" to layering of the substrate that might be conducive to the overall performance and longevity of a "High Frequency Wasting" type of plenum.

Ok, let's start with typical ( or standard ) type of plenum according to "Goemans", and start from there.

Let's try to pull from the center of the tank as much as possible ( details upon request ).

Let's also cram in as many feeder tubes as possible and use lots of rather small holes to "balance flow" across the substrate area.
Calculate these hole requirements to match the flow, don't guess please.

Put in the egg crate and screen just like the "Goemans" model. OOPS!!!! . . . WHOA THERE, HEH?

"Screen", is not very descriptive, and probably works fine in a "Goemans" style plenum, but this "might" deserve some consideration. I have screen on my plenum, and I'm not too worried about it. Mine has about 1.5mm ( or 1/16" ) holes in it.

Now here is where I may "throw" some people off, but I'll take it slow.

Let' start with the larger particles at the bottom, right on top of the screen. How about 3-5mm. That is not "sand", that is gravel. Let's use nicely grade stuff here and rinse it thorughly first .

Why, you ask, I'll get to that later. Let's just keep looking at this "model" for a few more steps here , Ok? Well, alright, I don't want anything to cause blockage around the plenum, you see.

1/2 " deep of this gravel should probably suffice from a "flow" standpoint. "But what about the anaerobic bacteria", you say, yeah, they'll be there, what about them?

Ok, how about, say, 1"depth of 2-4mm gravel above that? What's that for, you might ask? Well, . . . "Goemans" uses up to 4" depth of this stuff, so are you asking if it is too much, or too little?

The "hope" here is, that there is a lot of Anoxic activity in this "level" of the substrate. How thick is this Anoxic zone anyway, that everyone seems to know so much about? Remember the .5mm thickness of "Anoxic zone" mentioned previously in regard to DSB's?

All right, so here is where get to start "playing with it".

Now the 2-4 mm layer of gravel, is going to block "particle migration" down to about .3mm, that is three tenths of one mm. Don't think so, heh? Try me! Sorry, can't help it on occasion.

If you want to go with particles smaller than that, you may want to add, yet another layer of .7 to 1.7mm particles, say another 1/2" to 1", whatever.

Let's see now, were at 2" to 2 1/2" deep now right? ( from the "bottom up" )

Well, what do you want to do with it now? That is up to you of course, but for me . . .

Well I,m not going to be having "plugging issues" in the plenum now, because, I'm blocking "particle migration" with the afore-mentioned "larger gravel".

This seems a little bit counterintuitive, doesn't it? That is how I see it working.

Ok, for me, it is now a matter of what "critters", that I ( "we" )want to keep. H-m-m-m . . .

Let's put in a second screen here, to keep the "critters" from messing with our carefully controlled lower layers, heh? I'm thinking 6mm plastic mesh. I'm only trying to stop critters here, nothing else!

I like crabs, and snails, and pods, and cukes maybe, . . . micro stars maybe? Geeze, this is the part that is interesting here, because these animals could have some effect on the the "Oxygen Gradient" in the upper level of the substrate. right?

I think I might try some .7-1.7mm here, but I'm not so sure about how deep. The Gobies might like 3" of this, but that may not suit the "oxygen gradient" I'm looking for.

Oh well, more investigating to do!

What's next? > barryhc


:)

Membranes, channeling, plenum clogging, substrate, depth, bacteria populations, critters, variable individual setups, U-h-h-h-h ?

What is next? > Thanks all. > barryhc :)

[barryhc]

Originally posted by salty joe
Main Entry: dif·fu·sion
Pronunciation: dif-'yü-zh&n
Function: noun
1 : the process whereby particles of liquids, gases, or solids intermingle as the result of their spontaneous movement caused by thermal agitation and in dissolved substances move from a region of higher to one of lower concentration

This is what diffusion has always meant to me.

I think it's the "dissolved substances move from a region of higher to one of lower concentration" part that is probably the most meaningful to "us" here as "reef-keepers".

I think too many people have been using "it" as a reference to "water flow" in general that has caused some misunderstandings.

Thanks again! > barryhc :)

[voodoody]

barryhc,
I misunderstood your construction. Certainly egg crate on top of the manifold containing numerous small holes would not be disadvantageous. I have a similar number of small holes in my manifold. The test flushes demonstrated very rapid flow through the one inch center pipe of the manifold. This exits through a bulkhead at the bottom of my overflow and through another bulkhead on the tank bottom.

I do agree that the amount and frequency of plenum wasting is likely to be the key. ldrhawke was doing very frequent wasting and this may have resulted in an inabiltity to maintain the anaerobic zone.

I plan on flushing every 4-6 months or so. I am hoping this will rid the DSB of hydrogen sulfide and perhaps some accumulated metals at a minimum. I don't think I will be exporting much in the way of phosphates as this will be tied up in the bacteria. I am not expecting a massive die off of the anaerobic bacteria, but I will measure nitrates etc. to verify daily after I open the plenum valve.

[salty joe]

Membrane?

Did you read about substrate, gravel, plenum, eggcrate, screen, "critter blocking" screen, PARTICLE MIGRATION, etc., earlier in this thread?

Let me know if it remains a question.

Yes, I did read that but I don't understand how gravel will stop fine sand from finding its way into the plenum.

[CaptiveReef]

Originally posted by barryhc
Maybe we're getting somewhere here, but the "upper portion" of the bed needs to remain Aerobic in order to produce the NO3 in the first place, Right? ( unless you're favoring bio-balls, which I'm not )



CaptiveReef: Yes the upper portion of the bed will remain Aerobic which will produce Nitrate.

Then the Anoxic portion of "the bed" which is "under" this "Upper Aerobic portion, can perform the "work" that you describe. Am I still confused?


CaptiveReef: No your not confused, you got it!



Or less possibly, I don't know for sure about any magic number for Aerobic zone depth, I'm still looking for information, and I still believe that the zone depths will be other than published information if "simulated continuous flow" is performed on the substrate. > "oxygen gradation"

I'm still particularly interested in the Phosphate processing, that I seem to understand, is occuring in the "lower Ph" Anoxic and anaerobic portions of "the bed".

Any thoughts here?



CaptiveReef: The Phosphate processing in the Anoxic and anaerobic portions of the bed are pretty easy to explain. The Phosphate is eventually broken down into it's final form which is amino acids,Ref: Daniel Knop Giant Clams.
In the reef setup of course elevated levels of Phosphate will cause algae and inhibit the calcification process.
And here is another kicker, zooxanthellae need the following elements for photosynthesis, carbon dioxide, phosphorus, nitrogen, etc. Ref: Dana Riddle The Captive Reef.
I have always followed the practice of allowing these elements, but not at saturation levels.
With the use of a refugium, and Phosphate media, levels can be kept extremely low, but with this practice of doing the controlled draw from below the bed the waste levels will be removed before it can contribute to the phosphate production.

IMO I feel this Plenum/DSB draw will benefit the tank in the removal of waste that has been introduced into the bed from diffusion. It is a form of nutrient export. Hey I'm for it!!

CaptiveReef




Thanks again, this is progress. > barryhc :)

[voodoody]

CaptiveReef: The Phosphate processing in the Anoxic and anaerobic portions of the bed are pretty easy to explain. The Phosphate is eventually broken down into it's final form which is amino acids,Ref: Daniel Knop Giant Clams.

Amino acids contain only nitrogen, carbon, oxygen and hydrogen. The exception are methionine and histadine that contain sulfur as well. Phosphates are not incorporated into amio acids. There are numerous organic molecules that do incorporate phosphorus, however, including ATP and phospholipids of various types.

[CaptiveReef]

Originally posted by voodoody
Amino acids contain only nitrogen, carbon, oxygen and hydrogen. The exception are methionine and histadine that contain sulfur as well. Phosphates are not incorporated into amio acids. There are numerous organic molecules that do incorporate phosphorus, however, including ATP and phospholipids of various types.
I'm pretty sure this may cover phosphates ties with amino acids.
The 2nd to last sentence refers to phosphates.


THE 3-PHOSPHOGLYCERATE FAMILY OF AMINO ACIDS

Through this series of reactions, you should be noticing that there are common principles
that are used in the pathways again and again. Often, carboxyl groups are activated by
phosphorylation and then reduced to make an aldehyde before some other reaction occurs.
The series of reactions seen in the TCA cycle that react acetyl CoA with an alpha keto acid
and then proceed to shift an hydroxyl group and decarboxylate the product, are used in the
fungal lysine pathway and the leucine pathway. There are a variety of activating groups
that can be added to carboxyls and hydroxyls. These include phosphates, CoA, succinate,
acetyl groups or AMP. You should be aware of similarities in the different pathways.

In biosynthesis, all 20 amino acids are made from only 7 precursors from the central
metabolic pathways.

1. fructose 6 phosphate precursor to aromatic amino acids
2. glyceraldehyde 3 phosphate precursor to aromatic amino acids
3. 3-phosphoglycerate precursor to 3-phosphogycerate family of amino acids
4. phosphoenolpyruvate precursor to aromatic amino acids
5. pyruvate precursor to pyruvate family of amino acids
6. alpha ketoglutarate precursor to alpha ketoglutarate family of amino acids
7. oxaloacetate precursor to aspartate family of amino acids

[barryhc]

Originally posted by salty joe
Membrane?

Did you read about substrate, gravel, plenum, eggcrate, screen, "critter blocking" screen, PARTICLE MIGRATION, etc., earlier in this thread?

Let me know if it remains a question.

Yes, I did read that but I don't understand how gravel will stop fine sand from finding its way into the plenum.

A grain size of 2mm dia. will effectively block "migration" of "particles" down to .31mm dia.! Smaller particles will pass through.

How often do "we" change out "membranes" in RO units.

I don't want anything clogging the plenum. .3mm dia. particles will pass right through the .040" dia. ( 1mm ) holes that I have in my plenum. My plenum is not going to get clogged.

I will post a graphic representation some time soon. It's just Geometry.

Thanks > barryhc :)

[salty joe]

My concern is sand ruining the shutoff valve. I look forward to checking out your graphics.
Thanks,
Joe

[barryhc]

Originally posted by salty joe
My concern is sand ruining the shutoff valve. I look forward to checking out your graphics.
Thanks,
Joe

Thanks Joe, while I remain very interested in the Nitrate and Phosphate capabilities of the "wasting Plenum", It is really the plumbing outside the aquarium, that I haven't found time to put that much effort into.

I'm not overly concerned that it will represent a problem, but, it is questions like these that need to be dealt with, in order to have a "reliable" system.

Firstly though, I see it here, as a "design solution", to accomplish the original objective first, and then deal with "subordinate problems" in a practical fashion, without compromising the original objective.

I see the original objective as being the design and use of a "wasting Plenum" to process Nitrate, phosphate, and "whatever else", that we can process, or "waste". I am happy thus far with the "internal" portion of the design.

It is certianly time now, to consider "in ernest" the remainder ( outside portion ) of the system, and your concern here is appreciated.

My test setup is going "over the top", and then . . . . There will be many configurations.

My "big one" setup is going to be about 200 gal., and will probably be drilled etc., if I can pull that off.

Where can I get a glass tank with acrylic "bottom"? :D

I expect that particles etc. are going to exit the "plenum", and I particularly want them to. I believe that is important to the original function.

I remain intrigued with your original 2 valve "U tube" drain system. A "particulate trap" or filter may need to be incorporated.

If "we" trap this stuff in the substrate or plenum, how are we going to clean or change this once "filled up"? Get it?

Let's work on it some more and see what happens.

Thanks, > barryhc :)

[salty joe]

I plan on using Southdown sand and constructing a deep sand bed, only my sand bed would have a plenum underneath. I don't know how small Southdown sand particles are, but they are pretty tiny. So I do not envision any sizable particles working their way through the Southdown sand to clog things up, but maybe I'm wrong. I do know that Southdown sand is real hard on plastic parts that move. So I guess I was not quite right when I said no moving parts, there is a valve to turn. Maybe a two inch drain trap before the 1 inch valve would catch the sand. I have seen traps with a plug at the bottom to unscrew to release whatever is in there.

Concerning the U tube, the same thing could be achieved by running a horizontal piece of 1 inch pipe from the plenum drain directly to a verticle piece of PVC pipe (two or 3 inches perhaps) that is taller than the water level in the aquarium. Of course, you would still need a valve at the plenum drain and another at the very bottom of the vertical PVC.
Joe

[barryhc]

Thanks Joe. I agree that nothing significant is going to get through the Southdown Sand to block the plenum. It would likely be the Southdown Sand itself that would clog the plenum.

A shallow layer of 2-4mm gravel on top of the plenum screen should inhibit particles larger than .3 mm from getting into the plenum area to block your feeder holes. Then the "Southdown ", of course.

Only particles very close to the feeder hole size can block the hole. Try blocking a 1mm hole with a 2mm particle, It will fall away from the hole when the "flow" is off.

I'm working on that "Graphic" now. I have a 3 hr. scanner driver download "in progress". If "the old scanner" will run on the new xp drivers, I'll have some graphics this afternoon. ( I hope )

A 1.5" I.D. pipe holds .0077 gal. per linear inch, so 16" of this pipe would hold one pint of water. So for my case, 15" of this up to just above the tanks water level, with some 1/2" I.D. piping below, ought to give the 1 pint "waste volume" for my particular setup.

Am I with you here Joe? :D

My test setup ( the 27 gal. hex ) is going over the tank top with "U" tube, and then back down.

This means that I have some "intermediate volume" to consider "only when checking the effluent".

Otherwise, I don't think the second "U tube" collector that you describe causes any difficulty for anyone without "drilled tanks", like me. ( and obviously not for those "with" drilled tanks )

Automation and timing, are coming up soon here, for me, and anyone else who wants to use the "High Frequency" type.

Heh voodoody, can you send us to LDRHawkes' previous thread. I know he was using his computer with X10 technology at one point. Review would be prudent here.

Thanks all! > barryhc :)

[barryhc]

Joe, now that I'm correctly remembering the original "value" of your "U tube" idea, It seems that the U tube gizmo is going to allow us to accomplish a specific "draw volume", without any fancy timing for the draw volume itself.

Then "we" only have to time for the number of draws "per day", or "per week", or whatever. This is much easier than trying to switch pumps on and off for 5 second intervals etc.

We could also put a volume adjustment pipe into the collection pipe, from the top, to fine tune "volume" after the original installation. Now we don't have to be "overly fussy" about the exact draw volume , at the time of installation.

The "system" remains adjustable.

What do you Think? Thanks, > barryhc :)

[salty joe]

I don't plan on using any pipes with holes in them in the plenum. Just a deep sand bed with a plenum space underneath. The tank would have a drain in the middle of the bottom. When the plenum drain valve is opened, the entire plenum would be under negative pressure. It seems to me that this would pull fairly evenly across the entire bottom of the deep sand bed. And if the sand bed is constructed from Southdown sand, it would probably be a fairly slow draw.

To start with, I am considering draining about 10% of the plenum area once a week and fine tune from their.

The ability to adjust the volume of the collection pipe sounds good. I don't quite understand what you mean though. Details please.

[barryhc]

Originally posted by salty joe
I don't plan on using any pipes with holes in them in the plenum. Just a deep sand bed with a plenum space underneath. The tank would have a drain in the middle of the bottom. When the plenum drain valve is opened, the entire plenum would be under negative pressure. It seems to me that this would pull fairly evenly across the entire bottom of the deep sand bed. And if the sand bed is constructed from Southdown sand, it would probably be a fairly slow draw.

Yes, I see your plan. The entire area would be under negative pressure, however, that "vacuum" would not be "even". I can't say just how much imbalance that would represent. The thicker the plenum area ( water only ), the more even the vacuum. The slow draw would also help the "even-ness".

Originally posted by salty joe
To start with, I am considering draining about 10% of the plenum area once a week and fine tune from their..

I like the total monthly volume. At least we can fine tune this system, heh?

The ability to adjust the volume of the collection pipe sounds good. I don't quite understand what you mean though. Details please. [/B][/QUOTE]

The "particle migration" graphic first, I still have about 1 hour left on the scanner driver download.

If you put a smaller capped tube down into the "collection riser tube", the collection tube can't hold as much water.

Thanks > barryhc :)

[salty joe]

If you put a smaller capped tube down into the "collection riser tube", the collection tube can't hold as much water.


Good idea!

[barryhc]

Thanks Joe, My 3 hr. driver download failed. I'm on the phone with HP. "Voice-mail tag"! :mad2:

A threaded adapter at the top, or whatever, with vent holes, to allow filling, and keep bugs out. Change to whatever you want whenever you want. How could it get any easier?

Thanks again > barryhc :)

[voodoody]

The link to the original controlled plenum wasting thread is here:dsb heresey (http://reefcentral.com/forums/showthread.php?s=&threadid=289910&perpage=25&pagenumber=1)

Salty Joe, please explain your plan in more detail.
I don't plan on using any pipes with holes in them in the plenum. Just a deep sand bed with a plenum space underneath. The tank would have a drain in the middle of the bottom. When the plenum drain valve is opened, the entire plenum would be under negative pressure. It seems to me that this would pull fairly evenly across the entire bottom of the deep sand bed. And if the sand bed is constructed from Southdown sand, it would probably be a fairly slow draw.

I am not sure how this could be done without "short circuiting".

[barryhc]

Originally posted by voodoody
The link to the original controlled plenum wasting thread is here:dsb heresey (http://reefcentral.com/forums/showthread.php?s=&threadid=289910&perpage=25&pagenumber=1)


I read most of the thread, the first 3 pages, and the last 3 that LDRHawke posted in. He had a lot of people interested, and was doing some very very nice work. ( too bad we can't contact him )

Thanks for the link, I will probably review it some more. Hawke was way ahead of everybody there, and obviously ran into some Nitrate processing difficulties.

You might be right about the anaerobic zone, for his "schedule". My 3 draws of one pint each day came "almost directly" from Hawkes' information.

You might be moving way too far away with the 4-6 mos. frequency, and I may be "far too often" at 3 times a day. Whatever volume and frequency makes the bacteria "happy" should be the best.

I think I'm quite concerned with the "fabric cover" that Hawke was using over the plenum. That sounds like a "membrane", and it sounds like a "clogging" mechanism, that could promote "channeling", and also contribute to strange "floc" and associated bacteria populations, that could further promote "channeling", and I'm not sure whatever else. Whew!

I really think that we should be looking for reduced restriction, from the top of the substrate, down to the plenum, to avoid any kind of "plugging", or "clogging" anywhere in the substrate.

In any case, we have several seriously interested members with "us" here, and remember that "many" good and useful systems may result.

It is most likely that all "versions" of the "Wasting" system, are going to benefit from our understanding of the bacterial populations, and "oxygen gradations" that are being "promoted", with whatever version of "Wasting" that is being used.

Again, I am looking currently into the "High Frequency" type, and I have given a fairly good description of the plenum construction and also a "substrate model", for this particular type.

Your version might be deemed the "Low Frequency" type, and "might" deserve some different, or possibly even less demanding, construction or substrate requirements.

Long term use and testing will, of course, help all of us to learn, and then refine our use of a wasting system, to an improved potential.

I think we're having to work harder at this than the "DSB camp", or the "BB camp", because there just isn't enough data or "feedback" from the use of "wasting", and we will simply have to develop it.

None of us are in competition here, let's keep the good ideas, and reading links coming.

Thanks all! > barryhc :)

[DougSupreme]

here some pics of my plenum piping based on Ldrhawke's recommendations.

http://reefcentral.com/gallery/data/500/40195Picture_167__Small_.jpg

http://reefcentral.com/gallery/data/500/40195Picture_169__Small_.jpg

I used a 0.031 dia drill bit to make holes in the piping approx 3 inches apart. I also staggered the holes one at 10 o'clock and the next at 2 o'clock, alternating down the length of the pipes.

["Umm, fish?"]

DougSupreme,

That looks good. However, I'd be concerned that you don't have much in the way of crossing pipes. Yours will work, but you'll get much more even flow if you have more cross pipes. More like this:

|=|=|=|

than like this:

|===|

[barryhc]

Originally posted by DougSupreme
here some pics of my plenum piping based on Ldrhawke's recommendations.

I used a 0.031 dia drill bit to make holes in the piping approx 3 inches apart. I also staggered the holes one at 10 o'clock and the next at 2 o'clock, alternating down the length of the pipes.

Doug, that looks a fairly large tank. what size is it?

How many holes, just out of curiosity? How did you cover the plenum?

Have you been running the system, and can you report any results?

Welcome to the thread, and thanks for posting! > barryhc :)

[barryhc]

So, "Umm fish?", are you still in the "Low Frequency" category of interest?

It is perfectly fine, if you are, but I think there will be differences between "High" and "Low" frequency "wasting", and it would be beneficial to all concerned, if the type of "wasting" that you are developing is known, for clarity of communications.

Nice to see you back, and Thanks, > barryhc :)

[barryhc]

By the way Doug, I got a look at your gallery, and that in the wall implementation is really really nice. Is that about a 150 gal.?

Thanks again, > barryhc :)

[DougSupreme]

Originally posted by barryhc
Doug, that looks a fairly large tank. what size is it?

How many holes, just out of curiosity? How did you cover the plenum?

Have you been running the system, and can you report any results?

Welcome to the thread, and thanks for posting! > barryhc :)

It is a Perfecto 120G 5'L x 18"W

I have no idea how many holes, I suppose I could figure the number, I seem to remember that the holes were 3" apart. I simply wrapped the piping in landscape tarp( the fabric kind) and poured the southdown on top of that to a depth of about 4.5"


I have had the system up and running for over year. Unfortunately, I haven't really been recording any results up to this point, and my tank is scheduled to be torn down for a move in the next two weeks. When we move to the new house, I plan on setting the tank back up, so I should be able to record results .

["Umm, fish?"]

Nice to be back :D . I had to run off and be sick with my child and then have a birthday :( . Sucks getting old.

I am still in the "Low Frequency" category. I just think DSBs do what they do very, very well for a certain length of time. So, I just can't see screwing around with anything on a regular basis. Depending on what I find when I start sucking out of the bottom of the bed, I may pull about an inch off the bottom of the tank every 6 months or so and see how it goes.

I'll be really interested to see how the tank parameters change with each pull.

I have a theory, though. Tell me what you think. I think that no matter how we try we are going to get some channeling in our wasting. Further, I think that the anaerobic bacteria in these areas will survive our draws with no problems (since the water is channeling around them). And I think that these bacteria will very quickly re-colonate the rest of the SB after the draw, thus mitigating the parameter spikes that might occur.

I guess I'd better get experimenting.

But that's why I remain in the "Low Frequency/Higher Volume" category. So, what do you think?


So, "Umm fish?", are you still in the "Low Frequency" category of interest?

It is perfectly fine, if you are, but I think there will be differences between "High" and "Low" frequency "wasting", and it would be beneficial to all concerned, if the type of "wasting" that you are developing is known, for clarity of communications.

Nice to see you back, and Thanks, > barryhc

[barryhc]

voodoody, let's get back into some of these "zones" again. You had said that Hawke might have had a problem with "losing" his "anaerobic zone".

I'm not sure, that I want to lose it either, but, let's be very careful about calling a "zone" either "anaerobic", or "anoxic".

I don't think that you have made any errors regarding these terms, but I have seen them used "interchangably", or even worse, "in reverse", on many occasions.

This can lead to much confusion, and then controversy, based on miscommunication, and not misconception, both of which lead to most of the controversy.

Let's try to keep everybody straight about "Anaerobic" and "Anoxic" areas, and bacterial populations, as we proceed.

Now, about this "Anaerobic zone", I'm not sure why we need it, I'll admit. So as we try to explain its importance, let's try to keep the correct meaning ( or interpretaion ) of Anaerobic and Anoxic in mind, at least so that "I" won't get confused.

This should be beneficial to the rest of "us" as well.

You, "Kbmdale", and "CaptiveReef", at least, seem to be on the same page here, and maybe we can now get into the "functionalities" of these "zones", without getting lost in misunderstood terminology.

So, again, what is the Anaerobic ( VS Anoxic ) activities, that we are wanting to preserve, in a "wasting plenum"?

Sorry about the "long-windedness" here, but I really do want to keep this thread "educational", if not "very much more".

Thanks again, voodoody! > barryhc :)

[Obi-dad]

I am trying a different version of this, using the cpvc piping but with an SSB instead of a DSB. I have a DSB in my fuge, and like the looks of a sandbed, but don't want to accumulate crap in the sandbed (pun intended). So I have this drain system to hopefully remove some of the crap periodically. I don't have to worry about the anaerobic layer, because I don't have one to being with. The tank has only been up for 6 months, so hasn't really accumulated much stuff in the sand. My nitrates and phosphates are not measurable, and I don't have an algae problem (but I have a lot of chaeto in the fuge that grows quickly).

I'm not sure what frequency/qty I will drain yet. I have a few layers of weed preventer plastic around the pipes, and use Southdown sand, so I may not get the flow necessary, and it may still channel, but my only purpose is to flush water through, not to try and maintain an anaerobic layer, so it should be easier than the ones trying this with DSBs. Even if it doesn't work at all it was cheap to try, and shouldn't hurt anything.

[barryhc]

Originally posted by DougSupreme
It is a Perfecto 120G 5'L x 18"W

I have no idea how many holes, I suppose I could figure the number, I seem to remember that the holes were 3" apart. I simply wrapped the piping in landscape tarp( the fabric kind) and poured the southdown on top of that to a depth of about 4.5"


I have had the system up and running for over year. Unfortunately, I haven't really been recording any results up to this point, and my tank is scheduled to be torn down for a move in the next two weeks. When we move to the new house, I plan on setting the tank back up, so I should be able to record results .

Doug, "we" have a really great opportunity here, to see what happens during a "teardown" for one thing, and I wish you the best during the move.

You should have noted, that I am very concerned about "fabric", or anything, that even "vaguely" represents a "membrane".

Keep us with us here, in preperation for your "reinstallation".

Thanks > barryhc :)

[barryhc]

Originally posted by "Umm, fish?"
Nice to be back :D . I had to run off and be sick with my child and then have a birthday :( . Sucks getting old.


But it's great getting to be at birthdays and love your child!

Originally posted by "Umm, fish?"
I am still in the "Low Frequency" category. I just think DSBs do what they do very, very well for a certain length of time. So, I just can't see screwing around with anything on a regular basis. Depending on what I find when I start sucking out of the bottom of the bed, I may pull about an inch off the bottom of the tank every 6 months or so and see how it goes.

Sand beds might be able to do what they do "even better".

The 1" every 6 mos. does not sound the least bit severe, or "problematic".

Originally posted by "Umm, fish?"
I have a theory, though. Tell me what you think. I think that no matter how we try we are going to get some channeling in our wasting..

I agree, but I have been doing what I can to reduce this "channeling" to a "practical" level.


Originally posted by "Umm, fish?"
Further, I think that the anaerobic bacteria in these areas will survive our draws with no problems (since the water is channeling around them). And I think that these bacteria will very quickly re-colonate the rest of the SB after the draw, thus mitigating the parameter spikes that might occur.

That would be true, "if ", the "channeling" was that "severe", and, I am counting on exactly that perception to be true, in the "upper layer" of "my" ( or "the" ) "High Frequency" version.

I am also counting on something different to occur, in the "lower level" that I have described as the "substrate model" for "High Frequency" wasting.

You see, we can all be winners here.

Originally posted by "Umm, fish?"
I guess I'd better get experimenting.

I think so, and myself as well. I think "voodoody" is about ready as well.

You might be onto something, "Fish"!

That's what I think, and thanks again > barryhc :)

[barryhc]

Originally posted by Obi-dad
I am trying a different version of this, using the cpvc piping but with an SSB instead of a DSB. I have a DSB in my fuge, and like the looks of a sandbed, but don't want to accumulate crap in the sandbed (pun intended). So I have this drain system to hopefully remove some of the crap periodically. I don't have to worry about the anaerobic layer, because I don't have one to being with. The tank has only been up for 6 months, so hasn't really accumulated much stuff in the sand. My nitrates and phosphates are not measurable, and I don't have an algae problem (but I have a lot of chaeto in the fuge that grows quickly).

I'm not sure what frequency/qty I will drain yet. I have a few layers of weed preventer plastic around the pipes, and use Southdown sand, so I may not get the flow necessary, and it may still channel, but my only purpose is to flush water through, not to try and maintain an anaerobic layer, so it should be easier than the ones trying this with DSBs. Even if it doesn't work at all it was cheap to try, and shouldn't hurt anything.

For your intended purpose, as you state it here, I think that your reasoning is fairly "sound", however, I will continue to state, that whatever the purpose, anything like a "membrane" will "clog", and "channel", so if you want to avoid "clogging", I have recommended a "model" that will not suffer from this.

Thanks for posting Obi-Dad, barryhc :)

[wrasselover]

Interesting rehash of an old thread. About a year ago I contacted Hawke privately and got a response. He eventually stopped using his plenum system and went bare bottom. He said he reached a very simple conclusion. A plenum system could be made to work, but why treat waste in the tank, and be at risk of a biological over load and upset, when it is easier to design a system to remove the waste to start, and eliminate the major biological load that it causes.

I think he asked me something like....would you build a compost toilet in your house when it is cheaper and easier to flush a standard toilet. ?

[barryhc]

Originally posted by wrasselover
Interesting rehash of an old thread. About a year ago on contacted Hawke privately and got a response. He eventually stopped using his plenum system and went bare bottom. He said he reached a very simple conclusion. A plenum system could be made to work, but why treat waste in the tank, and be at risk of a biological over load and upset, when it is easier to design a system to remove the waste to start, and eliminate the major biological load that it causes. If you get your tap water from a commercial water system, that water is treated to make sure it's safe for human consumption. The water is cleaned, and filtered. Then, chemicals are added to the water to prevent anything harmful from growing in the water while it's in the pipe leading to your home. Until recently, most water treatment facilities used Chlorine to kill off any organisms in the water. The small dose of chlorine is safe to drink, but many people notice the slight chlorine odor. One problem water treatment plants have with chlorine is that it's unstable, and easily dissipated from the water. This means that the treatment plants need to put in higher levels of chlorine, so that they can be sure that some will remain in the water when it reaches your home. Recently, water systems have started treating tap water with chloramine instead of chlorine. Chloramine is a combination of chlorine and ammonia. It's much more stable than chlorine. It won't dissipate from the water as easily, and it isn't as likely to combine with other chemicals. But, chloramine isn't as good at killing off the microorganisms in the water as chlorine, so higher levels of chloramine are often used. Typically, water treatment plants use about 1 ppm of chloramine.

All this hard work and chemistry is important to keep people healthy. But, the same chemicals which keep people safe can be VERY toxic to fish. Adding tap water with chlorine or chloramine to a tank can kill off fish quickly. It can also kill off the bio-filter bacteria that keep your tank healthy and happy. So, this water must be made safe for the fish and tank. How do we do this? There are several common approaches, and their effectiveness varies depending on whether your local water treatment plant uses chlorine or chloramine. If you don't know which your water system uses, ask them.

I think he asked me something like....would you build a compost toilet in your house when it is cheaper and easier to flush a standard toilet. ?

Well now, "Wrasselover", you have had your "say".

Have you read this thread?

Who is "he"?

A "DSB" is a standard toilet. "We" are working "here", on "flushing it"!

So, what is your point?

> barryhc :)

[DougSupreme]

not to flame you, wrasselover, but what does anything in your post have to do with this thread? The whole middle of your post pertains to treatment of drinking water. The last statement where you paraphrase Hawke is pertinent...and accurate. BUT, we are trying to find ways to improve the efficiency of a sandbed, not remove it. Please don't think I'm trying to start something. I just think we need to stay focused in order to make any progress.

[wrasselover]

My orginal post contained a cut and paste error....... much shorter version reposted.

All I was doing was restating what hawke said to me on the topic.

[DougSupreme]

sorry, I didn't get the truncated version. Sorry for the negative post.

[barryhc]

By the way folks, I have not mentioned this previously, because I want to get the "logistics, of this "working", but I do not think that any "critters" are necessary, to make this system work, "necessarily". ( just bacteria )

Those who are trying to put a DSB over a plenum, may need this. I believe that it can work just fine for someone, with no "critters" at all, but the "substrate" selection for this will probably not be "DSB".

I prefer to have critters in the "upper level" of the substrate, and that is why I'm looking into "plenum wasting" to begin with.

I want the critters, and the substrate that they require. That's my reason anyway.

Thanks all, > barryhc :)

[voodoody]

barryhc,
conversion of amonia to nitrate is a process performed by aerobic bacteria (those that utilize oxygen in their metabolic pathways). The physical location of these bacteria might be considered an aerobic zone. This can occur anywhere, not just the top layer of a DSB (e.g. trickle filters, bioballs etc). Further conversion to nitrite and nitrogen (denitrification) is performed by anaerobic bacteria. The physical location of these bacteria might be considered an anoxic or anaerobic zone. I believe these terms can be used interchangeably. Some anaerobic bacteria are facultative (can use oxygen in their metabolic pathways if oxygen is present) and some are obligate anaerobes (cannot use oxygen ever and may actually sustain injury from prolonged exposure).
voodoody

[barryhc]

Originally posted by voodoody
barryhc,
conversion of amonia to nitrate is a process performed by aerobic bacteria (those that utilize oxygen in their metabolic pathways). The physical location of these bacteria might be considered an aerobic zone.

I thought that these Aerobic bacteria were converting to Nitrite, and then Nitrate. Are you sure that this not a "typo"?

Originally posted by voodoody
This can occur anywhere, not just the top layer of a DSB (e.g. trickle filters, bioballs etc). Further conversion to nitrite and nitrogen (denitrification) is performed by anaerobic bacteria.

Same as above. "TYPO"? Or, are you saying , "back to Nitrite"

Originally posted by voodoody
The physical location of these bacteria might be considered an anoxic or anaerobic zone. I believe these terms can be used interchangeably.

I'm not so sure about that. We need to be careful here.

Originally posted by voodoody
Some anaerobic bacteria are facultative (can use oxygen in their metabolic pathways if oxygen is present) and some are obligate anaerobes (cannot use oxygen ever and may actually sustain injury from prolonged exposure).
voodoody

That part I understand. So some "
Anaerobes" can become "faulative", in an "Anoxic" environment.

I thought, that you had stated that oxygen "is not toxic" to Anaerobic bacteria.

Still, what is the function that we want to maintain in the Anaerobic zone, with Anaerobic bacteria?

I thought we were dealing with Hydrogen Sulfide, and low pH Phosphate "re-solution", in the "lower" Anaerobic zone of the substrate.

Have I fallen off my stool? > barryhc :)

[barryhc]

Originally posted by voodoody
Some anaerobic bacteria are facultative (can use oxygen in their metabolic pathways if oxygen is present) and some are obligate anaerobes (cannot use oxygen ever and may actually sustain injury from prolonged exposure).
voodoody

I'm still particularly interested, with the "sustained injury", and the definition of "prolonged exposure". This is what I would hope to avoid with carefully controlled "draw depth" and "bacterial recovery time".

Thanks voodoody, let's work through this. > barryhc :)

[Obi-dad]

Originally posted by wrasselover
... but why treat waste in the tank, and be at risk of a biological over load and upset, when it is easier to design a system to remove the waste to start, and eliminate the major biological load that it causes...

What many BB'ers fail to realize is that many people like the looks of sand. BB is not a very good option if you want sand. It seems like the BB'ers keep trying to convert people who want sand. I understand that BB is an easier way of keeping the tank clean. But I don't need the easier path.

And for anyone considering putting a drain in the sandbed, you don't need to worry about all the anaerobic discussion if you are only doing an SSB, not a DSB. IMO, a good option to DSB in the dispaly tank is to have a DSB in a fuge (or even a bucket like Anthony Calfo suggests), and is much easier to change out later. This way you don't have to do a balancing act with maintaining anaerobic layers with the drain system.

["Umm, fish?"]

Not only that, DSBs are very good at what they do: they perform the nitrogen cycle all the way to getting the nitrates out of the system. They do bind up free phosphorus, but they don't complete a phos cycle. So, eventually they will fill with phos. And that's fine. Accept what they do very well, praise what they do very well, and let's find some way to work with their deficiencies. That's my battle cry.... :)

[barryhc]

Originally posted by Obi-dad
What many BB'ers fail to realize is that many people like the looks of sand. BB is not a very good option if you want sand. It seems like the BB'ers keep trying to convert people who want sand. I understand that BB is an easier way of keeping the tank clean. But I don't need the easier path.

Right on "Obi-dad"!!!

Originally posted by Obi-dad
And for anyone considering putting a drain in the sandbed, you don't need to worry about all the anaerobic discussion if you are only doing an SSB, not a DSB. IMO, a good option to DSB in the dispaly tank is to have a DSB in a fuge (or even a bucket like Anthony Calfo suggests), and is much easier to change out later. This way you don't have to do a balancing act with maintaining anaerobic layers with the drain system.

It shouldn't be that difficult, after installation, because we can choose whatever volume or frequency we like, and change to another schedule as well, at any time.

High Frequency types, like myself, may decide that once a week is adequate, or Low Frequency types, may want to try once a month, for whatever reason.

By the way Obi-dad, "some experts", have stated that Anaerobic activity starts at somewhere between 10 and 20mm deep in a "fine sand bed" ( oolitic-sugarsand ), so, how deep is a SSB?

I can't say that I happen to agree with these experts ( on where this activity begins ), but "many" see the "greater depths" as a "chemical sink" that lasts longer, the deeper it is. I probably do agree with that.

If we "waste" often enough, we may be able to remove some of these compounds, and bacteria that are "working on them ( in the "lower level" ), before the "binding process" is complete. That would be an advantage.

By the way, I expect to have a sand bed in my "fuge" as well. Great idea!

Thanks again > barryhc :)

[voodoody]

Barryhc,
Not really a typo, but I didn't tell the whole story. Nitrification occurs in the presence of oxygen and ammonia is converted by aerobic bacteria (via aerobic respiration) to nitrate and subsequently nitrite. Denitrification occurs in the absence of oxygen (anaerobic bacteria), but in the presence of readily reducible nitrogen sources. A mixture of gaseous nitrogen products is often produced because of the stepwise use of nitrate, nitrite, nitric oxide and nitrous oxide as electron acceptors in anaerobic respiration. So in the two different zones the nitrate / nitrite conversion is proceeding in opposite direction. I hope this make sense.

Voodoody

[Obi-dad]

Originally posted by voodoody
... and ammonia is converted by aerobic bacteria (via aerobic respiration) to nitrate and subsequently nitrite...

Voodoody

Actually aerobic goes first to nitrite, then nitrate.

[barryhc]

Originally posted by voodoody
Barryhc,
Not really a typo, but I didn't tell the whole story. Nitrification occurs in the presence of oxygen and ammonia is converted by aerobic bacteria (via aerobic respiration) to nitrate and subsequently nitrite. Denitrification occurs in the absence of oxygen (anaerobic bacteria), but in the presence of readily reducible nitrogen sources. A mixture of gaseous nitrogen products is often produced because of the stepwise use of nitrate, nitrite, nitric oxide and nitrous oxide as electron acceptors in anaerobic respiration. So in the two different zones the nitrate / nitrite conversion is proceeding in opposite direction. I hope this make sense.

Voodoody

It's to Nitrite, and subsequently Nitrate, in the Presence of . . .

This will "pass" shortly.

The denitrification is making sense. Anoxic, is a term that has been included in bacterial discussions, more often in recent times, and not so much in "earlier" studies and discussions.

Anoxic conditions are supportive of Faculative bacteria( at least ), converting Nitrite to Nitrate, and Anaerobic conditions "seem" to foster denitrification, and lower pH, along with Phosphate binding, hydrogen Sulfide production , and gosh knows what else.

Is this close?

Thanks > barryhc :)

[salty joe]

Voodoody,

I plan on setting up a deep sand bed that will be setting on top of a plenum. The plenum, or void area, will be about 1 inch tall. When the drain valve is opened, the entire plenum will be under negative pressure. Since I will be using Southdown sand, I do not expect water to exactly rush through it. So as I see it, the negative pressure at the corners of the tank will not be very much different from the negative pressure directly above the plenum drain. As far as short-circuiting, or channeling, is concerned, there is no doubt in my mind that that will occur to a certain degree. Since I will be removing a fairly small percentage of the plenum area at any given time, I am not very concerned about it.

The main reason that I want a deep sand bed is so that I can keep creatures like jawfish and certain anenomes. Plus, I like the look of sand.

Another thought on the collection pipe. It is my understanding that the water coming out of the plenum area does not exactly smell like a fresh sea breeze. A vented PVC cap could easily be constructed and filled with carbon.

If we keep this thread alive long term, there is no doubt in my mind that we can achieve a deep sand bed that will last indefinitely. I'm sure a lot of people think that this is a nutty idea, but this is the only way progress in this field or any other field for that matter is made.

[barryhc]

Originally posted by wrasselover
Interesting rehash of an old thread. About a year ago on contacted Hawke privately and got a response. He eventually stopped using his plenum system and went bare bottom. He said he reached a very simple conclusion. A plenum system could be made to work, but why treat waste in the tank, and be at risk of a biological over load and upset, when it is easier to design a system to remove the waste to start, and eliminate the major biological load that it causes.

I think he asked me something like....would you build a compost toilet in your house when it is cheaper and easier to flush a standard toilet. ?


So, why not design a system to remove the waste to start, and eliminate the major biological load that it causes . . . .

Then, go ahead and put in your plenum, and whatever substrate that you have decided on for whatever reason, and do as you please with your reef and your inhabitants.

Just a thought. That's what I'm doing. > barryhc :)

[barryhc]

RIGHT ON, SaltyJoe!!!!!!!!!

Just wathch out about that "membrane" idea. "plug", "plug" "plug"

We are getting somewhere, Joe, and you are helping a lot!

Thanks, > barryhc :)

[voodoody]

Obi-dad
Actually aerobic goes first to nitrite, then nitrate.

Yes, you are right. I did make a typo that time.

voodoody

[barryhc]

Originally posted by salty joe
The main reason that I want a deep sand bed is so that I can keep creatures like jawfish and certain anenomes. Plus, I like the look of sand.

Exactamundo!! especially the Jawfish!

Originally posted by salty joe
Another thought on the collection pipe. It is my understanding that the water coming out of the plenum area does not exactly smell like a fresh sea breeze. A vented PVC cap could easily be constructed and filled with carbon.

This is progress, absolutely!! I love it!

Thanks Joe, keep these good ideas coming. > barryhc :)

[voodoody]

Salty joe,
What is your plenum? How is your void area constructed?
voodoody

[salty joe]

This is all in the planning stages. My plenum will just be pieces of PVC supporting egg crate. I will put a piece of screen on top of the egg crate. If Barry can convince me (hint hint) that a layer of coarser sand will prevent the Southdown from entering the plenum area, that's the route I'll go. Anyway, from there it will just be a regular old deep sand bed constructed with Southdown sand. Probably about five or 6 inches deep.

[barryhc]

Originally posted by salty joe
This is all in the planning stages. My plenum will just be pieces of PVC supporting egg crate. I will put a piece of screen on top of the egg crate. If Barry can convince me (hint hint) that a layer of coarser sand will prevent the Southdown from entering the plenum area, that's the route I'll go. Anyway, from there it will just be a regular old deep sand bed constructed with Southdown sand. Probably about five or 6 inches deep.

Joe, the system that you are preferring, is just as likely at this point, to be a good system, as any of the others. We just don't have any better information yet. Of course, "we" will be developing it.

I will have "drivers" from HP by Oct. 4th. I have done a screen capture from "CAD", but it is 213 kb, and RC is not allowing that file size yet. ( I'm working on "them" )

In the mean time, take anything, that is vaguely 4" dia. ( or 2" dia. if need be ). Draw 3 circles that touch each other, and then draw a circle that fits into the remaining space between the three circlres.

That is all you will see when I can post the image anyway. Merasure the little circle, it will be 16% of the size, of the larger circles. Then think about it.

I hope this helps, and I love the charcoal, lets put a little "draw volume adjustment tube", right down the center of the carbon "destinker".

Thanks so much! > barryhc :)

[barryhc]

I have started a new thread called "Bacteria-Anoxic-Anaerobic?" in the "Advanced Topics" forum.

We can certianly continue to discuss bacteria here, but some of the material that I am finding and posting in the new thread is interesting, no doubt, but also, in some cases "rather heavy".

So just to keep this thread a lot "cleaner", I'll be looking in the new thread for "clarified" and up to date "bacterial process" information.

Thanks all, > barryhc :)

[voodoody]

Salty joe,
I am not a sewage waste expert. Idrhawke apparantly was. According to him, your planned construction will not work well as the lack of a reasonable number of discrete holes in the plenum will lead to large scale "short circuiting". According to him you will be detoxing only a very small percentage of your sand bed. Again, I am not an expert, but his original thread was quite convincing. I am convinced that his design (or a modification of it - such as the grid that I constructed) can work. The main issue is how much to drain and how often. I think that infrequent drainage is key to maintanence of the appropriate bacterial flora. I agree that this is difficult to prove.

[Obi-dad]

I need to explain about my posts - my sand bed drain system does not involve a plenum, and is not a DSB, just an SSB, so my system doesn't really fit in with the title of this thread.

[barryhc]

Originally posted by Obi-dad
I need to explain about my posts - my sand bed drain system does not involve a plenum, and is not a DSB, just an SSB, so my system doesn't really fit in with the title of this thread.

Just the same, Obi-dad, we are all interested in the bacterialogocal and chemical processes that occur in our tanks and in our substrates.

If you are draining, flushing, or wasting some water, and what's in it, from your substrate, you are "plenty close enough".

Originally posted by Obi-dad
And for anyone considering putting a drain in the sandbed, you don't need to worry about all the anaerobic discussion if you are only doing an SSB, not a DSB.]

By the way, an SSB works much the same as a DSB, in most cases, unless the depth gets "pretty short", like less than 1 1/2".
The shallower "bed" just has a smaller "chemical sink", which fills up faster.

If the "bed" is so shallow, as to not have this "chemical sink", then why would you bother to "drain anything from it?

Just a thought. > barryhc :)

["Umm, fish?"]

Hey! I got this off of the sulphur beads thread. Roadtoad says:


There was an article in Science a couple of months ago that dealt with the different environments in marnie sediments and the energy-producing chemistries that the resident bacteria utilized.


Did anyone see this article?

[voodoody]

Obi-dad,
Okay, I can see that. Shallow sand bed = less potential for short circuiting. Still get the better look of sand (compared to bare bottom). Remember though, since detritus removal will be harder than BB, you may need more live rock for denitrification than a BB or DSB system (unless you vacuum the sandbed very frequently).

[Obi-dad]

I have a DSB in the fuge, so my nitrates are zero. I am hoping this approach is the best of both worlds - the look of sand, no nitrates, and no (or at least not a much) 'sewage trap'.

[barryhc]

Originally posted by salty joe
If Barry can convince me (hint hint) that a layer of coarser sand will prevent the Southdown from entering the plenum area, that's the route I'll go.

Testing 1 - 2 - 3 - . . . .

http://reefcentral.com/gallery/data/4097/957994mm_Particle_Migration_45-100.jpg


So, this is just geometry. It seems simple enough to me.

The "gravel" should be "regraded" ( requalified ) by the user, using a screen with the same opening as the minimum size grade required, in order to remove the miscellaneous "dust and grit" from the intended substrate.

The gravel can then be used over a screen with openings at 75% of the size used for "grading".

Now you have a "gravel membrane". :idea:

> barryhc :)

[barryhc]

A few people have asked for graphics of the plenum design. I have had to do some piddling, to get the conversion working. I think I've got a handle on it now.

There is nothing very fancy here, just some PVC. The hole size and number, relative to substrate area, is a tad bit more interesting. There is some good information regarding number and size of holes, flow rate, frequency, volume, etc. in the first 8 posts on page 1 for those who are interested.

For Kris, voodoody, and whoever else, the graphics: :D

http://reefcentral.com/gallery/data/4097/95799Feeder_tubes_and_hole_points_70-100.jpg

http://reefcentral.com/gallery/data/4097/95799Hex_Plenum_Perspective_60-90.jpg

> barryhc :)

["Umm, fish?"]

That's certainly a beautiful design. I'm curious as to why you get a better flow from pipes branching from a center pipe rather than having all of the pipes connecting together with multiple cross-connections?

[barryhc]

Originally posted by "Umm, fish?"
That's certainly a beautiful design. I'm curious as to why you get a better flow from pipes branching from a center pipe rather than having all of the pipes connecting together with multiple cross-connections?

The shortest, and most "even" distance from a feeder tube extremity to the primary collection point, causes the most "evenly balanced" flow. It wasn't difficult to make.

> barryhc :)

[barryhc]

Here is a design for a 55 gal. setup.

http://reefcentral.com/gallery/data/4097/9579955_gal__plenum_perspective_80-90.jpg

The plumbing shown, is all 1/2" I.D. PVC. The connector manifold ( between the 2 sides ), could be lowered, by using two 45's in place of the two 90's shown.

In addition, the size and number of holes, would be appropriate, at 208 .047"( 3/64" )dia. holes. There are 52 individual "feeder tubes", so that's 4 holes, for each feeder tube.

A 3/4" I.D. "up tube" would also be appropriate here, and the 208 holes, would represent a 33% restriction to the 3/4" up tube.

This restriction improves flow balancing considerably. :idea:

Hey SaltyJoe, you got that carbon thing "rigged up" yet? :p

> barryhc :wave:

[CaptiveReef]

barryhc,

Just a suggestion with the drilling of the manifold, drill more holes in the outer tubes and as you get closer to the main draw tube connection, have fewer holes.
This will allow for a greater even draw in the manifold, there will be more suction from the holes that are nearest the main draw connection. Great design!!

:D CaptiveReef:D

["Umm, fish?"]

Sorry, I've been buried under work. I know that when pushing water _out_ and when it's important the water pressure be as close to the same for each hole as possible, the irrigation guys use a grid with many cross pieces. That's why I was curious.

[barryhc]

Originally posted by "Umm, fish?"
Sorry, I've been buried under work. I know that when pushing water _out_ and when it's important the water pressure be as close to the same for each hole as possible, the irrigation guys use a grid with many cross pieces. That's why I was curious.

That type of grid can be made to work, if the outer "rim" is larger than the feeder tubes. The restriction ratio, as mentioned above is highly beneficial to all designs.

Kbmdale has a graphic of that type of "grid" on page one.

Thanks for staying with us. > barryhc :)

[barryhc]

Originally posted by CaptiveReef
barryhc,

Just a suggestion with the drilling of the manifold, drill more holes in the outer tubes and as you get closer to the main draw tube connection, have fewer holes.
This will allow for a greater even draw in the manifold, there will be more suction from the holes that are nearest the main draw connection. Great design!!

:D CaptiveReef:D

That is quite true, but it raises other issues( area of substrate "covered" per hole ). In any case, for the 55 gal. example, 3 holes near the "collection point", then 4, and then 5, near the "ends".

In all cases, the aforementioned "relative flow rectriction" is very important to maintaining "flow balance".

Thanks Greg, > barryhc :)

ooPS: By the way, "substrate layering", draw depth, and bacterial recovery time, remain my currently most interesting aspects of High Frequency Wasting. :hammer:

[barryhc]

All right, you can call it "bumping" if you like, but there are many different potential approaches here, and yes, I am in the "High Frequency" version, so Ok, fine.

We've got the High Frequency approach.

We've got the Low Frequency ( or occasional )approach.

And then there is "layering" of substrates, or not.

Plumbing, Particle Migration, bacterial populations, oxygen gradations, too "complicated", ( yeah, right ).

Etc. . . . .

Let's keep it going folks, DSB's take 3-5 years( or more ) to explode, or cause problems. Maybe "never", some say.

No "magic bullets" tomorrow afternoon, sorry.

"WE" might have an option, 5 years from now, when the "----" hits the "fan", if the plenum is in there.

That's the big complaint isn't it, that "we" don't want to "tear-down" when everything has been "running so nice" up until "now".

So? > barryhc :)

[fppf]

Well, I read most of this thread (8 long pages, cut the chat geezs).

I have a lot of hydraulics and pneumatics background and some thoughts.

Have you tried doing a test draw in a tub with some food coloring streamers? I don't think your going to get the even flow your wanting. I would strongly suggest you setup this in a tub, then drop some food coloring in there but don't mix it. Then do a test draw and see if the coloring at the ends moves the same as near the draw pipe. I don't think it will given the fluid dynamics. Basiclly to have flow you need a delta pressure, each hole in the pipe will provide a way to decrease that delta pressure so by time you get to the end there wont be as much so then you get less flow through that hole.

As for the amount of water you want to pull its not going to be the volume of the area of the tank times you wanted depth. It will be that volume minus the volume the sand takes up. Depending on the size of grain used it will vary the amount of water actually held in the sand and then the limit of the draw to protect the teria.

As for a system to get the wanted flow pattern thats a little harder (IF the system now has flaws, testing needed). Think about this one. For a given area of sand you will have a maxium flow value based on the porosity of the sand and water colume above it. I would suggest to use a matterial that has the same porosity or a little less than the TOTAL sand bed. Then make the "plenum" or draw space the size of the wanted water draw. Then provide away to rapidly drain this area and replace it with a nitrogen purge. This would then allow for the fastest most even flow the bed could take. The amount of water moved would be limited when the space is filled backup with water again. The nitrogen would be pushed out through a vent as the water flows down.

I totally understand what your end need is and why you want to do it. But like what has been said, its going to take a lot of good testing and TIME to prove out a system. I don't even feel the true book writting "experts" have spent the time to prove out there ideas 100% yet.

[barryhc]

Originally posted by fppf
Well, I read most of this thread (8 long pages, cut the chat geezs).

I have a lot of hydraulics and pneumatics background and some thoughts.

> My hydraulics and pneumatics background is only experience, and plenty of it, but no formal training. Some of the statements that I have made are "seat of the pants" so to speak, but, I am ready to defend them right up to the "understanding"! :p

Originally posted by fppf
Have you tried doing a test draw in a tub with some food coloring streamers? I don't think your going to get the even flow your wanting..

> No, not with food coloring, but I did do a flow test for even flow at the "plenum" ( meaning through the feeder holes ), and it was consistent to within 10%. In other words, the plenum plumbing itself, flows consistently, pressure, or, "vacuum wise" to within 10%, using the "total feeder hole area" to "draw tube area" restriction ratio "method" for accomplishing "balanced flow", and that is again, 33-50% restriction, by way of total feeder hole volume, to "draw tube area". This will "fall-off" if "low flow rates" are used, which I insist on avoiding. "High Flow" only.

Originally posted by fppf
I would strongly suggest you setup this in a tub, then drop some food coloring in there but don't mix it. Then do a test draw and see if the coloring at the ends moves the same as near the draw pipe. I don't think it will given the fluid dynamics.

>If that test is conducted by anyone on my design, they will observe even flow balancing within 10%. I cannot conduct such a test now, because the plenum that I built is under 6" of substrate, and 35 #'s of live rock.

Originally posted by fppf
Basiclly to have flow you need a delta pressure, each hole in the pipe will provide a way to decrease that delta pressure so by time you get to the end there wont be as much so then you get less flow through that hole.

> And that is the reason for "CaptiveReef's" suggestion for "more holes near the extremities", and that is one of several remedies, available to counteract "delta loss" near the "extremities".

Originally posted by fppf
As for the amount of water you want to pull its not going to be the volume of the area of the tank times you wanted depth. It will be that volume minus the volume the sand takes up. Depending on the size of grain used it will vary the amount of water actually held in the sand and then the limit of the draw to protect the teria.

>You are quite right here, and thank you very much! One pint of flow, on my system, might now be 1", if we find that "substrate typicaly uses up 87.5% of the "available volume". Thanks for the contribution, "we" all needed that. ( very important seriously! )

Originally posted by fppf
As for a system to get the wanted flow pattern thats a little harder (IF the system now has flaws, testing needed).

>All systems will have flaws, we must overcome this with better information. Until we know more about the depths of these bacterial processes, we cannot accurately estimate the appropriate depths of the "substrate", relative to the "Bacterial recovery time", relative to downward "flowrate", "relative" to E=MC squared. ( and Particle Size, of course )

I could easily bombard this thread with mathematical formulas, that I can take right out of my head ( and further with real fancy ones that I will research, just as soon as anyone gets past the "former" ) until it only took a "Nano-Second" for everyone to "head for the hills" ( or down one of Bombers'
"worm holes" ) on this idea. I have been very careful not to do so.

If this project is going to be successful for the "Typical aquarist", it must be understandable in reasonable "laymans terms".

Typical Aquarists are rather intelligent people, so far as I have noticed anyway.

Originally posted by fppf
Think about this one. For a given area of sand you will have a maxium flow value based on the porosity of the sand and water colume above it. I would suggest to use a matterial that has the same porosity or a little less than the TOTAL sand bed.

> Huh? Is this "relative" to "Particle Migration", or something else? Material for what? ( TOTAL what? )

Could you "expound" on this? ( "I don't get it" )


Originally posted by fppf
Then make the "plenum" or draw space the size of the wanted water draw. Then provide away to rapidly drain this area and replace it with a nitrogen purge. This would then allow for the fastest most even flow the bed could take.

Look, I'm listening here, but you're "gonna hafta" run "thatun" by me "agin there pardner".

Originally posted by fppf
The amount of water moved would be limited when the space is filled backup with water again. The nitrogen would be pushed out through a vent as the water flows down.]

And the "function" here is?

Originally posted by fppf
I totally understand what your end need is and why you want to do it. But like what has been said, its going to take a lot of good testing and TIME to prove out a system. I don't even feel the true book writting "experts" have spent the time to prove out there ideas 100% yet. :p

Or 20% for that matter, in this case, but you are quite right.

Look, this may have seemed a bit "reactionary", if you like, but, I've left you with some questions, and if there is something else that you think that I am not understanding properly, by all means, "lay it out here". :p

And thank you very much for becoming involved, "we" need all the help we can get!]

> barryhc :) :thumbsup:

[barryhc]

You know, I said before, some "real engineer" ought to come in here, and just "kick my a$$". I hope this fellow is up to it.

It couldn't hurt could it?

> barryhc :)

[fppf]

How did you come up with the 10% numbers may I ask?

Yes you can try to compensate by chaning hole sizes and by having the total area of the drilled holes less that the area of the final drain pipe.

I work with some of the brightest and best engineers everyday. I work in the aerospace and military aircaft industries. Before that I worked at a company making pressure and flow transducers.

Anyway, even the best engineers test the numbers. Fluid dynamics has a lot of "Black Art" its right up there with RF and high GHz band width stuff.

My idea I'm trying to relay here is to make almost a trickle filter effect in the plenum. If you remove all water under the plenum faster than the water can flow through the sand and replace it with a low pressure nitrogen space then the pressure would be totally equal across the whole bed. The trick is to not let any gas up into the bed, which is where the barrier would come into play. It would help make it so there is always a positve pressure gradiant.

[barryhc]

Ok, let's see.

So we have a 1/2" I.D. "pipe", and we're using .047" dia. holes in this pipe.

Now this 1/2" I.D. pipe, has an actual I. D. of about .580 to .600 of an inch right?
So, this .590" Dia. hole, has an area of .2734 sq. in. right?

All right now, so these .047" dia. holes are going to have an area of .00173 sq. in. right?

Ok, so now this first .047"dia. hole is going to reduce the "Continuing Delta factor" by .633% right? we're all still here now aren't we?

So, now the "continuing Delta" is only 99.367% right?

Well, "alrighty then". So, by the time we get to the flow, from the 52nd hole, at the extremity of each central collection point, on the 55 gal. design, we're going to be looking at 72% right?

Now let's apply CaptiveReefs idea about a different number of holes near the extremities.

So, 5/3 = 167% right? . . . "times" 72% = 120%, right?

So that's a bit too much at the "extremities".

Well, I guess that's a little bit of "overkill", but I guess we get the idea, heh?

> barryhc :p

[barryhc]

Well, I see what you're relating to here with the nitrogen purge, and I don't work for NASA or anything, just a "Old Crusty Fart", I guess.

We're pasiing replies again already, I always find this "comical".

The Nitrogen purge is well taken, but do you have any response to the reply that just got "passed"

Thanks again, > barryhc :)

[fppf]

There is a lot more to the problem than just the hole size. Yes its a start, a very good start. But every elbow, joint, inside surface of the pipe, flow tubulance and tons of other factors will change the results. Now granted a lot of varibles will have only a little change and can be ignored. Its the unknown factors that you lead me to want to test the system in the real world. I have seen a lot of stuff work on paper but not follow the "laws" when on the bench.

Man keep your panty hose on, I'm multi tasking here.
Trying to finish the BOM for my tank controller.

[fppf]

Hey, how did you think I know how to work with Titanium if I was not in aerospace :D

[barryhc]

Originally posted by fppf
Hey, how did you think I know how to work with Titanium if I was not in aerospace :D

Ever hear of "Ultasonic Horns", I've made a lot of them. Ti-6Al-4v.

I make the best titanium ultrasonic horns, anywhere in the world, I kid you not!

> barryhc :)

[barryhc]

Originally posted by fppf
There is a lot more to the problem than just the hole size. Yes its a start, a very good start. But every elbow, joint, inside surface of the pipe, flow tubulance and tons of other factors will change the results. Now granted a lot of varibles will have only a little change and can be ignored. Its the unknown factors that you lead me to want to test the system in the real world. I have seen a lot of stuff work on paper but not follow the "laws" when on the bench.

Man keep your panty hose on, I'm multi tasking here.
Trying to finish the BOM for my tank controller.

Atta Boy!

But if you look at the graphics of my design, posted in this thread, you will see that all of those factors have been very, and I say again, very carefully minimized, and consider the people who are concerned with what they see as the "overkill" in my design, as it is!

Besides, like I said, I did test it! want some details? > barryhc :)

[fppf]

I'm all about details, thats where the devel is.

It says something to work with Ti, but you already know that.
Does your proccess require you to weld or just machine. Not that machining it is easy, but welding adds that extra little plus! Every try to drill "Super Invar"

[barryhc]

Originally posted by fppf
I'm all about details, thats where the devel is.

It says something to work with Ti, but you already know that.
Does your proccess require you to weld or just machine. Not that machining it is easy, but welding adds that extra little plus! Every try to drill "Super Invar"

No, never heard of "Invar", but I've done Hastelloy grades "B", "C", and "D" along with Pure Nickel( yeah I said 100% pure ) Inconel, Tantalum ( now that is a Bi---! ), and a good number of particularly "Exotic" materials, along with 7 grades of "plastics", and some "G10" glass material for Fermilab.

Got into some "Electron Beam Welding" years ago, having to do with the "Joint US-Soviet Space Mission' in the 70's.

Life is Is a "Box of Chocolates"! > barryhc :p

[fppf]

Oh yeah, we did some Hastelloy
Our oil industry pressure xducers where Inconel X750.
Anyway we are getting off topic here.

[barryhc]

Well, a little engineering "banter" there, heh? It's not so difficult, really, and "fppf" is quite right about testing.

It's quite easy to do "before installation" and can be done before gluing as well, so it is well worth it to have no "nagging doubts", once you start pouring in the "sand" ( or whatever ). It wouldn't be all that hard to make a new set of feeder tubes with holes, if you were disappointed with the test results.

I put mine on the pool deck, and fired up a 175gph power head. My feeder holes happen to be drilled both in the top and the bottom of the feeder tubes, and when the water squirted up, it was between 6" high near the center, and 5.5" high at the ends.

This was of course, on the little hex. version. and it should be carried out on any system before installation. Probably about a 350 gph Powerhead for the 55 gal. version. No "Black Art" after this test.

I think that the "delta loss" values calculated previously, are not quite accurate, because of the central manifold tube design, and not having taken into account the 33-50% restriction factor.

I will "delve up" some real accurate flow loss calculations for this shortly to include friction loss over tube length, etc., unless of course "fppf" would like to handle this for us ( hint, hint ).

And the point made by "fppf", about the ratio of "volume of water in the substrate" to the "volume of substrate, that water is in", is truly a revelation. I really needed that.

This might put my 7/64" draw depth value up to 7/8" in the substrate, while it becomes about 5/32" in the plenum area, due to the space the plenum itself takes up, in my particular design.

I don't think this calculation of water space taken up by the plenum itself, is of much concern really, but the draw depth is particularly important to me regarding the bacterias' response to Oxygen input.

So, now it would only take 8 days for this oxygenated water to reach the plenum ( in 7" depth of substrate ), at 7/8" per day, and 1 "one pint draw" per day.

That's still about 4 gal. per month, which is about 20% of the 20 gal. of actual water, in my particular 27 gal. hex tank. Not that bad, as a water change volume. Randy Holmes Farley has shown, that daily water change intervals are no less than 74% as efficient as monthly water changes, of the same total monthly amount. That's good enough for me, at least I'm not using too much water here, and I can change any more out that I like with other methods.

I'll keep looking for information on the bacteria, and how they might respond to periodic oxygenation. I really want to keep an Anaerobic ( no oxygen ) area in the bottom 1" or so of the substrate itself, above the plenum, for Phosphate and "nasties" processing.

So, off we go again, let's see where it leads us. Thanks all, > barryhc :)

[fppf]

That sounds like a valid test, one would think the numbers would work out the same or close when the draw is do, aka flip the sign.

Have you gave any thought to how much delta pressure will be needed to get the wanted flow through the sand bed?

Maybe the answer to the oxygen problem is to get rid of the oxygen? Maybe a second manifold about an inch or so below the surface of the bed could inject water that is anoxic, the you could flush as much as you want.

[barryhc]

Originally posted by fppf
That sounds like a valid test, one would think the numbers would work out the same or close when the draw is do, aka flip the sign.

Have you gave any thought to how much delta pressure will be needed to get the wanted flow through the sand bed?

Well no, actually, because "we" haven't been able to establish what the depth and particle sizes are going to be. For my setup, I'm "leaning" towards about 7" of Arag., layered as such:

> 3/4" of 3-5mm directly above the plenum screen
> 3/4" of 2-4mm above that
> 3/4" of .7-1.7mm above that
>> then the "critter screen", probably about 6mm openings here to stop "critters" only.
> 2" of "oolitic" ( sugar ) sand
> 2 3/4" of 1-4mm

Were up to the surface here, and there wont be any "sandstorms" in my tank, even with flow at 30-40 times the actual water volume.

Originally posted by fppf
Maybe the answer to the oxygen problem is to get rid of the oxygen? Maybe a second manifold about an inch or so below the surface of the bed could inject water that is anoxic, the you could flush as much as you want.

H-M-M-M- . . . I think that the bacterial populations need to process the nutrients "down" ( diffusion ) to get the best nutrient processing done in what I now call the "low oxygen zone". this is what I'm working on the most lately, is the bacterial processes. Below this "low oxygen" area, we have the "no oxygen" zone which I hope to be an inch or more thick, and where sulfide, and other "nasties" are normally processed. This is the area where most "DSB crashes" supposedly come from, and is what we want to "waste".

I made a thread, for the investigation of proper nomenclature, and these nutrient and compound processing bacteria, called "Bacteria-Anaerobic-Anoxic"? in advanced topics.

There some excellent links there. Another one, is "Biological Phosphorous Removal", which has some good information, including anoxic and anaerobic bacterial processing and "forced oxygen level" fluctuations that "they" are using in Municipal Water Systems. This includes "Phosphate processing", and is exceedingly intresting.

I'm not throwing out the second manifold idea, but I have to think about it a "good bit". I'm pretty patient about these things, and I like to let "the soup" simmer awhile before it's ready for "serving".

Thanks, > barryhc :)

[barryhc]

You know, as I review the previous post with the "layering model" that I'm considering for my particular set-up, it occurs to me, that the lower layer, or layers of the bed, need not be aragonite.

In fact, why has everyone been "running toward" aragonite anyway? Now it's got some porosity to harbor bacteria I believe, but wasn't the big "feature" supposed to be calcium and alkalinity buffering? Isn't this buffering supposed to occur because of low pH, and isn't it because of the substrate "melting" in the low pH, and isn't that what causes some form of "P leaching", that is complained about a lot?

Now if we're wasting frequently, then why would we care about the P, if it is going "down the toilet" anyway? But why have our "gravel membrane" melting, and eventually clogging and falling through the lower screen, when we could use a less soluble "substrate down there near the plenum. The bacterial activity "down there is going down the drain as well, so?

If calcium and alkalinity can be managed reasonably in a bare bottom system, then certianly, it can be managed in a "substrate" system just as easily.

I want the "sand and gravel" because the critters want it! And I like to look at it. ( and the critters )

If we can process some nitrate in there in the upper layers, then good, of course, and if we can dump some waste from that process "out the bottom" while we're at it, then "so much the better"!

So, in my case here, if the wasting plenum "avoids the crash", my objective is accomplished. If the system processes nutrients better, then that is very worthwhile also.

What is your objective here? "Chime in for sure"! > barryhc :)

[inwall75]

Ouch.

I read the WHHHHOOOOOLLLLEEE thread.

I just communicated with LDRHawke via a different bulletin board the other day and it is true that he isn't using this method anymore. (I don't know him at all). However, he stated that he did get it to work well. His reason for stopping using it wasn't because it failed. He just wasn't interested in critters that require sand so it didn't make sense for him to continue with it.

BTW....he hasn't stopped experimenting. Check out his bubble filtration in the main tank. http://homepage.mac.com/johnlaurenson/ReefTank/Personal41.html

In fact, why has everyone been "running toward" aragonite anyway? Now it's got some porosity to harbor bacteria I believe, but wasn't the big "feature" supposed to be calcium and alkalinity buffering? Isn't this buffering supposed to occur because of low pH, and isn't it because of the substrate "melting" in the low pH, and isn't that what causes some form of "P leaching", that is complained about a lot?

The "big feature" is HIGHLY overrated. I've run both BB and DSB systems and while I've never measured it, I can tell you via observation that you truly aren't getting the buffering that is widely accepted as fact. Are you getting a little...sure. But I'll tell you what, sand is the MOST EXPENSIVE buffer there is. Does the P leach into the water column from the bottom levels. Not likely as bacteria will grab onto quickly or it will readsorb to the CaCO3 in the higher levels where the pH is higher.

P can leach into the water column with a typical sandbed after a period of time. However, this particular system, if done properly will take care of the problems that lead to this.

[barryhc]

Thanks Curt, So it appears that we have at least one vote for phosphate processing, and we can widen our horizons on what can be used for substrate.

I think that for occcasional wasting, substrate material may be a bit more important, but for frequent wasting, you can probably use just about anything, below the top 1 1/2". Particle size, is a different story, however, and the discussion remains open of course on it's effects relative to bacteria etc.

Any thoughts Curt, or anyone, on specific oxygen saturation levels and the related bacterial activity, as well as bacterial recovery time?

Thanks again Curt, need any "Murine or Tylenol" after that long read. :D > barryhc :)

[barryhc]

Ok folks, so I'm "bumping the thread". I have stated before, that this is a "long term" project, and I do not expect it fail.

Some people "do or will" consider this, too complex to "fiddle with". I submit that a captive reef system is complex, and that will not "go away".

I do expect that when enough is known about the bacterialogical processes, and how they are affected by "forced downflow", that a considerable level of improvement will have been identified, for those reef keepers who wish for whatever reason, to operate a reef system that utilizes "substrate" for the well being of animals that prefer or require it, and/or for the enthusiast who simply prefers "the look" that is coincidentally available.

Others, may have ideas about the implementation, and insights or concerns, regarding the health of the bacterial populations within the "substrate".

I will state again that this only a supplement, or sub-function of the "system" as a whole and that good husbandry, water flow, skimming, species seletion, parameter testing, and on et. al., is necessary to maintain any reef system for the long term.

Thanks to all, and happy reef keeping > barryhc :)

["Umm, fish?"]

Hey! I was just thinking that it was about time to bump the thread again. Have you starting sucking water yet? If so, did you test the waste? Any numbers?

I just about have my grid built. Silly hardware store ran out of 1/2" crosses, so I have to wait for a bit.

Cheers!

Andy

[barryhc]

Originally posted by "Umm, fish?"
Hey! I was just thinking that it was about time to bump the thread again. Have you starting sucking water yet? If so, did you test the waste? Any numbers?

Cheers!

Andy

No, I have been trying to get done with my "spring yard work" before next spring arrives, and I'm designing a refugium, and it has a DIY skimmer in it ( that requires a good bit of investigation as well ), and . . . .

Oh well, I will start drawing water from the plenum pretty soon. I will start with a "manual draw" of 1 pint, once a day. That is supposed to be 7/64" of water column "down flow" each day. If you have been following the thread closely, you should understand that this represents approx. 7/8" of "downflow distance" in "the substrate" itself. Please ask about this if you do not understand what is being said here, it is absolutely crucial to the understanding of bacterial populations, and their recovery rate.

Thanks for posting, this going to work, I am quite sure. > barryhc :beachbum:

[inwall75]

Originally posted by barryhc
Thanks Curt, So it appears that we have at least one vote for phosphate processing, and we can widen our horizons on what can be used for substrate.

I think that for occcasional wasting, substrate material may be a bit more important, but for frequent wasting, you can probably use just about anything, below the top 1 1/2". Particle size, is a different story, however, and the discussion remains open of course on it's effects relative to bacteria etc.

Any thoughts Curt, or anyone, on specific oxygen saturation levels and the related bacterial activity, as well as bacterial recovery time?

Thanks again Curt, need any "Murine or Tylenol" after that long read. :D > barryhc :)

Or at least Phosphate recycling.

Since the last time I read this thread, I've been running around with my head chopped off. Someone please remind me. Has there been any discussion of an inline pH monitor to determine the pH of the water being drawn off? That could be very useful IMO at determining if you've drawn off too much water or if a smaller amount of water was drawn off too quickly.

Bacterial recovery time is so difficult for me to wrap my head around. Here's why. Provided the proper Oxygen environment, the only thing that needs to occur to have a very quick recovery time is sufficient nutrients. The bacterial population grows on a logarithmic basis every 30 minutes or so IIRC. 1 bacterium would be 2 and in 30 minutes you would have 4 and so on. Look at these numbers and you can see just how quickly they can grow.

1,2,4,8,16,32,64,128,256,512, etc. Since we are going to be starting out with much higher populations to begin with our only limiting factor is going to be how quickly the combination of diffusion and bacterial migration will get Nitrogenous compounds into the sandbed.

[barryhc]

Originally posted by inwall75
Or at least Phosphate recycling.

Since the last time I read this thread, I've been running around with my head chopped off. Someone please remind me. Has there been any discussion of an inline pH monitor to determine the pH of the water being drawn off? That could be very useful IMO at determining if you've drawn off too much water or if a smaller amount of water was drawn off too quickly.

Bacterial recovery time is so difficult for me to wrap my head around. Here's why. Provided the proper Oxygen environment, the only thing that needs to occur to have a very quick recovery time is sufficient nutrients. The bacterial population grows on a logarithmic basis every 30 minutes or so IIRC. 1 bacterium would be 2 and in 30 minutes you would have 4 and so on. Look at these numbers and you can see just how quickly they can grow.

1,2,4,8,16,32,64,128,256,512, etc. Since we are going to be starting out with much higher populations to begin with our only limiting factor is going to be how quickly the combination of diffusion and bacterial migration will get Nitrogenous compounds into the sandbed.

All right, now "I" am trying to get my mind around "this". "Sort-of".

You see, I have always felt "instinctually" that this wasn't going to be that much of a problem, for the very reasons that you state, but, there has been so much "riff-raff" about how the "entire bacterial population" is going to "be destroyed", that I have found it difficult to proceed.

There is going to be a "gradation" in the oxygen level of the substrate, and that gradation is going to be "modified" by "Wasting", as I have stated "forever", but the downflow can br tuned to cause this gradation to occur in the way that "we" desire, If we can determine what it is that we desire.

So, whether it is pH, or oxygen, or better yet both, the evaluation of "effluent" is going to be "key" to developing "the system".

I don't think there is any way for us to know ahead of time, and the reason I've been working so hard thus far, "ahead of time", is
in order to develop the "substrate model", and you can see that I have gone to a "layering scheme", which drives a lot of people "bonkers".

I have the little hex tank, which is my little experiment, but I'm getting ready for a 200 to 300 gal. tank in December, and I will have decided about the "substrate model" by then.

So, Curt, I think you are right on here, with the "testing", and I hope to start "drawing and testing" within a week.

Please stay with us here, your input is highly valuable.

> barryhc :beachbum:

[inwall75]

Originally posted by barryhc
You see, I have always felt "instinctually" that this wasn't going to be that much of a problem, for the very reasons that you state, but, there has been so much "riff-raff" about how the "entire bacterial population" is going to "be destroyed", that I have found it difficult to proceed.

I completely agree with you. Here's an interesting experiment. Take a small piece of a frozen prawn, put it in an airtight rubbermaid container and immediately put it in the fridge to thaw out. Wash your hands ahead of time but not with an antibacterial soap. Then mix up some saltwater (i.e. not tank water) and add it to the rubbermaid container. Then take a small amount of sand out of the sandbed in an established tank. You don't have to add a 6 inch sandbed. Lay the sand out on some paper towels so that the sand is dry. I can guarantee you will see that small piece of shrimp rot even though supposedly, we've nearly wiped out all of the bacteria. Over a period of time, you could do Ammonia, Nitrite, and Nitrate tests on the container and you will see a cycle...all started from airborne bacteria.

You could do this exact same thing without adding sand. Airborne bacteria would be in there fairly quickly. Bacteria are highly adaptive. They don't merely migrate to the proper areas, they will create their own environment. There is Nitrification AND denitrification occuring in a biofilm so thin on your front glass that you can see through it. They can create any Oxygen condition they need to. Can these biofilms handle the typical bioload of a reef tank? NOT EVEN CLOSE. That's why the Berlin method of adding LR completely changed this hobby. More surface area=more bacteria=more nitrification.

Originally posted by barryhc

There is going to be a "gradation" in the oxygen level of the substrate, and that gradation is going to be "modified" by "Wasting", as I have stated "forever", but the downflow can br tuned to cause this gradation to occur in the way that "we" desire, If we can determine what it is that we desire.

So, whether it is pH, or oxygen, or better yet both, the evaluation of "effluent" is going to be "key" to developing "the system".

I don't think there is any way for us to know ahead of time, and the reason I've been working so hard thus far, "ahead of time", is
in order to develop the "substrate model", and you can see that I have gone to a "layering scheme", which drives a lot of people "bonkers".


My thought on the pH moniter is basically that you can deduce Oxygen levels via pH. IMO, you can decide when the draw it too much, too quick, etc. THAT IS if you are terrified of killing all of the bacteria. If you tried to do a 6" sandbed made of oolithic grains on top of this plenum, I truly believe that it would take some time for effective denitrification (that can support a typical reeftank) to be re-established. However, what you are doing is setting up a system of removing waste, nutrients, and solids, but since you are using a more open pore-space between grains, they should re-establish quickly. What we have to remember....what we DON'T want in our water column, is life-giving food for bacteria.

BTW, the reason I think that people go "bonkers" is because there is no hard and fast rule. People beg to know watts per gallon for lighting, gallons per hour of flow, etc. This is an unknown that you are delving into and you are correct, experimentation is the only way.

[barryhc]

Originally posted by inwall75
I completely agree with you. Bacteria are highly adaptive. They don't merely migrate to the proper areas, they will create their own environment. More surface area=more bacteria=more nitrification.

Curt, are you familiar with the "supposedly" very thin "low oxygen zone" that supports "Faculative-non-obligate-anaerobes" that are supposed to be responsible for much of the "Nitrite to Nitrate" processing in a "sand bed"?

I have found this originally in the "Goemans and Gamble" literature, but also in very many other "professional studies and dissertations". Waste treatment is "rampant" with such discussions, as well as some advanced "disections" of "Vodka Dosing" and similar "forced bacterial activity" endeavors.

My thought on the pH moniter is basically that you can deduce Oxygen levels via pH. IMO, you can decide when the draw it too much, too quick, etc. THAT IS if you are terrified of killing all of the bacteria.

Well, I'm not, but it would be good for verification that the "bacrerial population" is being "controlled". And a "report" from a controller to a "log" would be extremely helpful. I'm working on this currently, as a side investigation on "controllers".

If you tried to do a 6" sandbed made of oolithic grains on top of this plenum, I truly believe that it would take some time for effective denitrification (that can support a typical reeftank) to be re-established.

I,m losing it here, please explain. We should not have to re-establish a bacterial population, if we did not decimate it in the first place, which is the primary function of "High Frequency" VS "occasional" plenum "Wasting".

However, what you are doing is setting up a system of removing waste, nutrients, and solids, but since you are using a more open pore-space between grains, they should re-establish quickly.

You should look at my "layering-scheme" earlier on this page, or on the last page. While many systems might come from this investigation, the "High Frequency" version is being "touted" almost exclusively by me. I insist that "solids" should be removed nearly identicaly to a BB system, by way of the "substrate layering scheme", high-flow, "live-rock elevation", and with "critters", that keep "poop", algae, and detritus in suspension, for skimming and or mechanical filtration. ( skimming highly preferred here )

Bacteria populations should not need to "re-establish", for any depth or distance greater than that which causes them "no difficulty whatsoever".

High frequency wasting, should create an oxygen gradation that is effectively "permanent and continuous". Any "recovery" should only need to occur over a very short distance, like 1/8" to possibly as high as 1" in the substrate, and "never" any "oxygen flushing" of the substrate, that would require any re-establishing of the bacteria population to occur over any period of time longer than "SAY" 1 or 2 hours, and for not more than a "distance or depth" of more than about 1/2".

What we have to remember....what we DON'T want in our water column, is life-giving food for bacteria.

H-m-m-m-m . . . Well, I think I might be following you here, you mean Nitrates and phosphates, for algae growth, and "let's skim everything we can", or am I missing the meaning here?

BTW, the reason I think that people go "bonkers" is because there is no hard and fast rule. People beg to know watts per gallon for lighting, gallons per hour of flow, etc. This is an unknown that you are delving into and you are correct, experimentation is the only way.

Well, no "magic bullet" for sure, and you are again, right on, that experimentation, testing of effluent, and tank parameters, is paramount.

I've been a bit "picky" with you here Curt, but it is for accuracy, and not for offense or defense of "anything".

Please stay with us, I particularly appreciate your input. More of what you have stated here has been taken "to heart", than might be immediately obvious!

Thanks again, barryhc :beachbum:

["Umm, fish?"]

If you tried to do a 6" sandbed made of oolithic grains on top of this plenum, I truly believe that it would take some time for effective denitrification (that can support a typical reeftank) to be re-established.

I think this would be true only if one effectively drained the entire sandbed. I think that no matter what we do there will be channeling in the bed that will leave areas of the bed relatively unscathed. I think the bacterial population in the bed will be able to recover from the untouched areas pretty quickly.

[barryhc]

Originally posted by "Umm, fish?"
I think this would be true only if one effectively drained the entire sandbed.

I agree entirely.

I think that no matter what we do there will be channeling in the bed that will leave areas of the bed relatively unscathed. I think the bacterial population in the bed will be able to recover from the untouched areas pretty quickly. [/B]

I have gone to a lot of trouble to avoid channeling, and I think to good effect, however, I agree that some channeling might still occur, and while I do not think that it will unduly "compromise" the remainder of the bed, I agree, that the affected areas should be able to recover rather quickly.

The "lower layers" below the "critter screen" are intended to remain "stable", and allow for these fluctuations in the "upper layers".

Good points "Fish".

> barryhc :beachbum:

["Umm, fish?"]

To really explain why I think channeling is okay, I think I need to explain my theory of why DSBs "leak" (I hate that term) phosphate. So please bear with me and please tell me if I'm way off-base (or even a little off-base :) ). This is all simplified, but it's how I organize the problem in my head:

All populations of critters are limited by many factors. Now DSBs give bacteria huge chunks of real estate to call home, but it is still a finite resource and they reproduce like mad, so living space can eventually be a limiting factor of the bacteria population.

The bacteria in our sand bed not only participate in the nitrogen cycle, they also bind phosphate. Not much (they're small), but there are enormous numbers of them.

When a bacterium dies, the stuff it's binding in it's "body" gets released.

A lot of the phosphate we put into our systems never makes it back out again.

If you take all of these factors into consideration, you can see that the bacteria in the sand bed will take in and hold the phosphate we add, PLUS all the phosphate that's been released from every bacterial generation, right up to the point where the bacterial population runs out of room to expand. At that point, there will no longer be phosphorous uptake (by the bacterial population).

So the question you have is: how does this apply to anything?

I want to drain my DSB infrequently to a) get any crap out of the bed I can and b) to kill off a subset of the bacteria to open up real estate for expansion. If I drain infrequently it gives the sand bed time to settle back down and the bacteria time to re-colonize.

That's my reasoning. Please shoot holes in it. :D

Andy

[barryhc]

Originally posted by "Umm, fish?"
All populations of critters are limited by many factors. Now DSBs give bacteria huge chunks of real estate to call home, but it is still a finite resource and they reproduce like mad, so living space can eventually be a limiting factor of the bacteria population.

How long is eventually?

The bacteria in our sand bed not only participate in the nitrogen cycle, they also bind phosphate. Not much (they're small), but there are enormous numbers of them.

When a bacterium dies, the stuff it's binding in it's "body" gets released.

A lot of the phosphate we put into our systems never makes it back out again.

Yes, I'm following here.

If you take all of these factors into consideration, you can see that the bacteria in the sand bed will take in and hold the phosphate we add, PLUS all the phosphate that's been released from every bacterial generation, right up to the point where the bacterial population runs out of room to expand. At that point, there will no longer be phosphorous uptake (by the bacterial population).

H-m-m-m . . .

I want to drain my DSB infrequently to a) get any crap out of the bed I can and b) to kill off a subset of the bacteria to open up real estate for expansion. If I drain infrequently it gives the sand bed time to settle back down and the bacteria time to re-colonize.

Well, I follow just about everything that you are saying here. I have a few points to make, regarding the benefits that I expect to receive from wasting frequently.

>Firstly, I am lazy, and I hate water changes. I am absolutely dead serious here. Frequent Wasting will cause a "continuous water change" to occur automaticaly, and forever. For me that is a very nice feature. "Continuous water changes" are 74% as effecient as monthly water changes of the same monthly volume, and that is good enough for me. At the 1 pint per day for my system, that is equivalent to a 17% water change monthly. I highly prefer this continuous condition to "all at once" water changing.

I would have to go to considerably more trouble to put together an automated water change system here, so "complexity wise" this is just easier and less expensive anyway.

>>Secondly, frequent wasting will "stretch" the bacterial populations, causing the aerobic zone to be a "bit deeper". This top Aerobic zone is only about 1/2 to 1" thick to begin with, and may become up to 1/2" thicker, but not more, so what is the problem with that?

The "low oxygen" zone comes below this where most processing of Nitrite to Nitrate occurs, and it is generally regarded to be only about .5 to 1mm thick. This is where "non-obligate-Anaerobic-faculative- bacteria" do Nitrate "processing. This is generally accepted fact by many "authorities" on the subject, and if it does not "sit well" with anyone, then this is where the bacterialogical discussion needs to continue!

The "stretching" of the bacteria populations, could increase the depth of this "low oxygen" zone to between 3-6mm thick, which would represent a 4 to 8 times factor of improved Nitrate processing power. I like that too!

So now, "we" have used up about 1 1/2" to 2" of the top level of the substrate so far, and in my 7" deep "substrate model", that still leaves us with at least 5" of remaining substrate for the Anaerobic zone. Gee, I don't see that as being inadequate, and it allows probably at least another 3 to 4" of substrate to account for my conceptual errors, or whatever else a person ( or critter )might want it for.

This "oxygen gradation" will be controlled by frequency and "draw depth" as necessary, and THERE WILL NOT BE OXYGENATED WATER anywhere near the plenum!!!!!!!!!!!!!!!!!!!!!!!! period.

>>>Thirdly, this process will be "effectively continuous", which eliminates concerns about "what happened when I wasted the plenun". There is no "when I wasted the plenum", because I am "always wasting the plenum".

So while some ( or a lot of ) "diffusion" will continue to occur, relative to the "water column", in the top 2" or so, the nastier processes "below" have plenty of room, and most of it is "on it's way down" anyway!

It is not undergoing some questionable "big change".

That's my reasoning. Are there any holes in it? :hammer:

Thanks, > barryhc :beachbum:

[reefclown]

The "low oxygen" zone comes below this where most processing of Nitrite to Nitrate occurs, and it is generally regarded to be only about .5 to 1mm thick. This is where "non-obligate-Anaerobic-faculative- bacteria" do Nitrate "processing. This is generally accepted fact by many "authorities" on the subject, and if it does not "sit well" with anyone, then this is where the bacterialogical discussion needs to continue!

Barry, how far have you considered the possibility of biofilms that coat every available surface area in the tank, i,e the entire cycle occurs within a microns layer on every availabe surface regardless of the presence of 'sediment zones'

here's a random sulphur based extract that demonstrates the concept, there are millions of accredited marine biofilm articles out there.

http://aem.asm.org/cgi/content/full/65/11/5107

i.e. do you accept that biofilms coat every surface and in themselves are capable of completing the full nitrogen/sulfur//phosphate/e.t.c cycle at the micron level?

Isn't all that remains a method of gettind the most detritus out of system before it has chance to cycle in the biofilms?

I'm a technologist by trade who neglected bio after further education and am also enjoying the learning of a new area in later days

;)

Jerel could tell us in a few words, but that simply would not be right, some direction would be nice though:bum: :cool:

I apologise if this was covered earlier in the tread.

edit: another usefull article
http://aem.asm.org/cgi/reprint/62/12/4641

["Umm, fish?"]

How long is eventually?

No real clue, but the consensus seems to be 4-5 years, if the sand bed fails at all.


Firstly, I am lazy, and I hate water changes. I am absolutely dead serious here. Frequent Wasting will cause a "continuous water change" to occur automaticaly, and forever. For me that is a very nice feature. "Continuous water changes" are 74% as effecient as monthly water changes of the same monthly volume, and that is good enough for me. At the 1 pint per day for my system, that is equivalent to a 17% water change monthly. I highly prefer this continuous condition to "all at once" water changing.


Me, too. I putting overflow drains on my sump. So, a water change is turning off the auto top-up and turning a valve. The WC water displaces old water out of the sump. I stole that idea out of Calfo's book.

I like the idea of stretching the bacterial populations. That's good.

>>>Thirdly, this process will be "effectively continuous", which eliminates concerns about "what happened when I wasted the plenun". There is no "when I wasted the plenum", because I am "always wasting the plenum".

Right, but what if the bacteria population needs recovery time? I have no idea, personally. Time will tell, I guess.

Are you going to run an O2 or pH probe down into the bed to check O2 levels? Or do I remember a discussion about this earlier. It all gets a bit fuzzy.... :rolleye1:


Cheers!

Andy

[barryhc]

Originally posted by reefclown
Barry, how far have you considered the possibility of biofilms that coat every available surface area in the tank, i,e the entire cycle occurs within a microns layer on every availabe surface regardless of the presence of 'sediment zones'

here's a random sulphur based extract that demonstrates the concept, there are millions of accredited marine biofilm articles out there.

http://aem.asm.org/cgi/content/full/65/11/5107

Within a "microns layer", what is that?

This is from reading in the link that you supplied:

FIG. 1. A cross section made with a cryomicrotome (20 µm thick) of an aerobic domestic wastewater biofilm. The biofilm thickness is approximately 1,000 µm. ( 1000 microns )

That is 1mm thick, which is .039". This is a bit thicker than 1/32".

1mm is the thickness that I stated previously regarding the "low oxygen" zone. This value is considered to be valid, in "oolitic" sand, and would be considerably thicker in a larger particle size of substrate.

I do not have any visible bio-films in my tank that are thick enough to see. This may be because of the brittle stars, and snail and crab populations. I get an exceedingly thin film on the glass after about 2 weeks, but since I clean the glass weekly . . . .

My live rock has coraline and feather dusters, and otherwise looks like "cooked rock". Same condition for 6 months. I don't stir, I don't vacuum, I don't siphon. I have proper aquascaping, 25 x flow, and skimming.

i.e. do you accept that biofilms coat every surface and in themselves are capable of completing the full nitrogen/sulfur//phosphate/e.t.c cycle at the micron level?

No, not at the "micron level". I deal in "tenths of a thousandth" everyday, which translates to 2.5 µm. I am INTIMATELY FAMILIAR with these "distances". One of your hairs is 90 microns thick, OK?

Isn't all that remains a method of gettind the most detritus out of system before it has chance to cycle in the biofilms??

No, detritus does not just cycle in the "bio-films', it creates them.
Don't allow detritus to collect in your system, REGARDLESS OF "BOTTOM TREATMENT"!!!!!!!!!

Read the first post in this thread, right on page 1 of coursre. This thread is for those who WANT TO RUN SUBSTRATE IN THEIR SYSTEM FOR WHATEVER REASON ! ! ! ! ! ! ! ! ! ! ! ! ! !

I don't mind that much if you are happy with BB. They are fine in very many cases, however, PLEASE read all of page 1, and the last two pages of this thread, if you expect to offer meaningful comments.

> barryhc :strooper: :hammer: :beachbum:

["Umm, fish?"]

I'm sorry, but I must take us a little off-topic (and we are trying to avoid that).

I don't understand why BB tank people use live rock. So many make the argument that sand beds are mysteries and therefore they don't want them in the tank. Isn't the live rock a mystery, too? Wouldn't bare egg crate shelves serve the philosophy a bit better?

Okay, rant off. No more.

[reefclown]

Barry,
firstly my apologies for not having read the thread, having now read it I can see why your response is somewhat hostile.

No, not at the "micron level". I deal in "tenths of a thousandth" everyday, which translates to 2.5 µm. I am INTIMATELY FAMILIAR with these "distances". One of your hairs is 90 microns thick, OK

Barry, I'm not questioning your familiarity with distances!

In the context of this tread my last statement was insenstive/unconstructive as was any implied reference to BB, please disregard.

OK, hopefully misunderstanding cleared up and we are on a CLEAN SLATE.
----------------------------------------------------------------------------------
Now, let me attempt to rephrase what I was meaning to ask.

The thread appears to be evaluating a method of controlling bacterial activity within a sediment layer. And the core of the discussion looks at the effects of bacterial activity within that sediment under varying circumstances.

I was simply meaning to ask what activity you believe occurs at a smaller scale, for example on the bacterial film that coats a single grain of sand. Is this bacterial film capable of completing the full nitrogen cycle. i.e does the bacterial film covering the grain of sand contain aerobic, anoxic and anaerobic zones/bacteria within it?

I'm simply asking you to consider a lower denominator, as it may aid in the understanding of how the sediment will operate when the oxygen gradient changes.


from the link provided

O2 consumption took place in the upper 50 to 100 mm of the biofilm, with a rate of 0.81 6 0.13 mmol z cm22 z h21. The production of NO3 2 plus NO2 2 appeared in the same layers....
Denitrification in the layers below 150 mm ranged from 0 to 0.28 mmol z cm22 z h21, with an average of 0.11 mmol z cm22 z


in a reduced oxygen variant of the experiment (I thought you may have found this interesting as you are looking to determine the effects when changing the oxygen gradient in the sediment bed).

Incubation with reduced O2 concentration (115 mM) decreased both O2 penetration and metabolic rates.The O2 concentration reached levels of less than 20 mM on the biofilm surface and zero within 25 to 75 mm of depth. The total oxygen uptake was 0.35 6 0.07 mmol z cm22 z h21, whereas the production of NO3 2 plus NO2 2 decreased to 0.28 6 0.14 mol z cm22 z h21 (averages and 95% confidence limits for 10 different profiles, respectively). The main activity of nitrification was found at a depth of approximately 20 to 50 mm, and denitrification occurred in the deeper layers (100 to 200 mm), with an average rate of 0.10 mmol z

so in effect rather than the 1000 microns you mentioned earlier a more realistic target figure MAY be in the range 10-300 microns ? everything below 300 microns being anaerobic. Add degradable organic matter to the above equation and the nitrifying layer will reduce yet further?


The "low oxygen" zone comes below this where most processing of Nitrite to Nitrate occurs, and it is generally regarded to be only about .5 to 1mm thick. This is where "non-obligate-Anaerobic-faculative- bacteria" do Nitrate "processing. This is generally accepted fact by many "authorities" on the subject, and if it does not "sit well" with anyone, then this is where the bacterialogical discussion needs to continue!

I hope this goes someway to explaining why the above does not still well, and hopefully open up the discussion in the areas you intended.


peace:bum:

[barryhc]

Originally posted by "Umm, fish?"
No real clue, but the consensus seems to be 4-5 years, if the sand bed fails at all.

All right, that seems to be what I find as well, including the "if at all". Plenums have failed, DSBs have failed, BB systems have failed. So what. I want the sand and gravel so that the critters can live in it. I am trying to get good reliability out of it primarily, along with some processing, whatever "we" can get "reliably".

But I require it for the critters, not for "processing". I am going to have sand and gravel in my tank, FOR THE CRITTERS period!

I like the idea of stretching the bacterial populations. That's good.

A-h-h-h . . . you're getting the "stretch idea", fantastic! I must not have presnted much of this as well as I could have, because Ihave been viewing this on the basis of a "continuous-stretch" of the bacterial populations since Dec. of 2004, a long time before I started this thread.

Right, but what if the bacteria population needs recovery time? I have no idea, personally. Time will tell, I guess.

The bacteria are going to be affected by drawing water from the plenum. Water treatment facilities are getting very good at this( although some of them argue as much as reefers :lol: :lol: ). A very new "process" uses only one "vessel" and cycles between aerobic and anaerobic only ( or so they think ), which is very close to "draw water" then "wait", "draw water" then "wait".

This is in fresh water, not salt water, and they are not "exactly" the same, but . . . . . Time will tell, I'm sure!

Are you going to run an O2 or pH probe down into the bed to check O2 levels?

I would like to run O2 and/or pH probes, but my understanding is that these probes only last so long before needing cleaning and or replacement, and "servicing" the probe, would disturb the environment were trying to monitor.

I need to find out more on this. I had intended to monitor O2 and Phosphate in the effluent, and the P is still relevant to monitor here, but oxygen may change as it travels through the plenum piping and could be changed considerably if it takes two days for plenum water to actually exit the end of the plenum piping. This might be the case depending on the volume of the plenum piping, even while the "draw"remains "high flow" and "short duration" ( like 5 seconds).

You know, as I'm writing this, I'm wondering about a DIY "water extractor", that would at least let us get a representative "sample" of the water, to test "outside" of the tank, as usual. It could be made from 1/4" I.D. PVC by 1" long, capped, and plumbed with 1/8" I.D. tubing, then run outside of the tank. This would be constructed like a little "micro plenum". Several of these, say, one for every inch of substrate depth, could be installed, along with the plenum, and drawn from, before and after "wasting" to monitor various parameters, and fluctuations.

Please don't get me wrong here, "Fish" or anyone else. I still believe that several versions of this "wasting" idea, might be found to work well, and I'm not really opposed to other versions, but I still find the "High Frequency" type to fit my expectations thus far into the investigation. If I run into a hitch, especially with Bacteria, I'll run from it like a forest fire, but that is not what I have been finding.

"Fish", what think ye, of the "micro plenum water sampler"?

> barryhc :beachbum:

[barryhc]

Originally posted by reefclown
OK, hopefully misunderstanding cleared up and we are on a CLEAN SLATE.
----------------------------------------------------------------------------------

so in effect rather than the 1000 microns you mentioned earlier a more realistic target figure MAY be in the range 10-300 microns ? everything below 300 microns being anaerobic. Add degradable organic matter to the above equation and the nitrifying layer will reduce yet further?

I hope this goes someway to explaining why the above does not still well, and hopefully open up the discussion in the areas you intended.

Thanks for the reply, ReefClown, you are quite gracious. I think that these processes are actually occuring at both ends of this spectrum, but it is where they "predominate" that I have been putting emphasis on. You can tell now, that I have been more interested in bacteria than anything else, since the thread started. The mechanics, just aren't that difficult.

All questions need to be answered, just the same. I hope everyone understands that I DO NOT KNOW IT ALL HERE!!!

I will know enough by Christmas, when my 200-300 gal. tank goes in.

ReefClown, our replies have "passed during typing". This happens fairly often. Consider my last post, I wrote it before I saw "your last", so it is not "in response". I am a slow typer.

I have to leave right now, not enough time to really respond, I will read, consider, evaluate and respond, possibly by tommorow.

Thanks for joining us here, learning is the goal.

> barryhc :beachbum:

["Umm, fish?"]

Hey! I finished roughing out my grid tonight! :rollface: Now I just need to put my drill press together that showed up today and make some holes!

You gotta love Amazon. A 95 lb. drill press. It qualified for free shipping because of the price and they lived up to it. Delivery to my porch, absolutely free!

I would like to run O2 and/or pH probes, but my understanding is that these probes only last so long before needing cleaning and or replacement, and "servicing" the probe, would disturb the environment were trying to monitor.

What do you think about running a piece of pvc with ID large enough to hold the probe down through the sand layer; holes for water flow only at the bottom (inside the bed); cap on top with a hole drilled for the probe wire?

The probe can be taken in and out with minimal disturbance of the bed.

As for the micro plenum water sampler, I don't see what benefit you gain over just testing the waste water. I was thinking that some sort of probe might give you a idea of when you need to waste before you suck water out. If you used a controller with the probe you might be able to automate the whole thing.

Happy weekend!

[salty joe]

Hi Barry,
You asked a while ago if I had put a carbon cap on the collection pipe. Unfortunately, I am in the planning stages and will be there for quite some time.
The discussion on testing the effluent is interesting. Your idea of taking water from different parts of the plenum to see what happens after a draw is an excellent idea.
Am I off-base for thinking that testing for phosphate in the effluent will tell the story? I was thinking that once consistent phosphate readings were achieved, a balance had been struck and the sand bed could last indefinitely. Or am I all wet?

I also wonder if a less scientific test of the effluent would be useful. Like maybe get a vial of effluent and check it for color against a color chart. Maybe even notice if the smell is different.

Anyway, I find this thread very interesting and now I will go back to the lurking mode.
Joe

[reefclown]

Been thing about the 'pull' mechanism, and thought about an old reverse flow sand filter design from Frank De Graaf in the 70's that could be adapted to provide a simpler mechanism.

here's a sketch of an adaption.


http://www.ultimatereef.net/uploads/wastingp1.jpg

It removes the need for a manifold and should allow for an even pull through the sediment bed. The pull pipe can be placed at any depth and simply tapped.

any thoughts?

[barryhc]

Originally posted by "Umm, fish?"
What do you think about running a piece of pvc with ID large enough to hold the probe down through the sand layer; holes for water flow only at the bottom (inside the bed); cap on top with a hole drilled for the probe wire?

The probe can be taken in and out with minimal disturbance of the bed.

As for the micro plenum water sampler, I don't see what benefit you gain over just testing the waste water. I was thinking that some sort of probe might give you a idea of when you need to waste before you suck water out. If you used a controller with the probe you might be able to automate the whole thing.

I don't think I can get good oxygen information from the waste water, and I want to monitor many parameters, at many depths and locations CHEAPLY. The "micro plenums" cold cost as little as $20 for about 28 0f them. I might actually use that many.

This idea is not for the average installation of one of these systems, but is instead, only for me to learn about what is going on for both my, and everyone's benefit.

Having one probe mounted in a fashion similar to what you propose, for the pupose of automation, may be a good idea, if we can find a probe that will last long enough, when continuously submerged.

Thanks, > barryhc :beachbum:

[barryhc]

Originally posted by salty joe
Hi Barry,
You asked a while ago if I had put a carbon cap on the collection pipe. Unfortunately, I am in the planning stages and will be there for quite some time.

I was particularly enjoying the progress we were making then, on the "cheap-simple-automated-volume" control. I like the system that had developed at that point, with one caveat, for me anyway. That is that I remain somewhat adamant about "high flow", and that set-up is going to slow down to "zero", in a linear fashion, and that is a concern for me. I haven't thought about it since, to solve that problem, but it remains on my "burner".

Last I remember, we had "no-stink", and adjustable automated volume, "on the cheap" and easy.

The discussion on testing the effluent is interesting. Your idea of taking water from different parts of the plenum to see what happens after a draw is an excellent idea.
Am I off-base for thinking that testing for phosphate in the effluent will tell the story? I was thinking that once consistent phosphate readings were achieved, a balance had been struck and the sand bed could last indefinitely.

I am interested in Phosphate, pH, and oxygen primarily, the "micro plenum", or whatever we call it, lets us test for anything-anywhere-anytime, so to speak.

I am very much in the planning stages for my "big tank". You needn't "lurk" so deeply, come up for "oxygen" more often!

> barryhc :beachbum:

[barryhc]

Originally posted by reefclown
Been thing about the 'pull' mechanism, and thought about an old reverse flow sand filter design from Frank De Graaf in the 70's that could be adapted to provide a simpler mechanism.

It removes the need for a manifold and should allow for an even pull through the sediment bed. The pull pipe can be placed at any depth and simply tapped.

any thoughts?

I don't see where this is very much different than an under gravel filter plate. It could be made to work with some modifications for better flow balancing. Drill holes in the bottom plate, or elsewise cause a "flow restriction" between "above and below", then cover with egg crate and screen to "disperse" the draw between the lower plate and screen. The restriction is crucial to balanced flow, and still requires high flow to "effectively balance".

Thanks all. >barryhc :beachbum:

ooPS: I haven't had time to review on bacteria, but it remains my highest interest, along now, with post installation "testing".

[reefclown]

Sediment composition aside, would it be fair to say that:

A plenum in it's basic mechanical sense in an undergravel filter with a broken airlift?
A wasting plenum is akin to an undergravel filter whereby the passing of water through the sediment bed is "controlled and wasted" rather than continuous and recycled ?

If

1.the screen and sediment composition is as you propose in your current design,
2.the plenum void space is also the same,

then the shown diagram simply equates to replacing the manifold with a tap, right ?

I'm trying to get my head around how adding a manifold improves the dynamics of waste extraction and can't quite grasp it at this moment. Am I missing something fundamental ?

["Umm, fish?"]

Actually, having a plenum void space around the manifold might be the best best. There'd be no sand around the manifold to impede the draw. That said, I don't think I'll bother, for reasons stated farther up the discussion.

[barryhc]

Originally posted by reefclown
Sediment composition aside, would it be fair to say that:

A plenum in it's basic mechanical sense in an undergravel filter with a broken airlift?
A wasting plenum is akin to an undergravel filter whereby the passing of water through the sediment bed is "controlled and wasted" rather than continuous and recycled ?

That is very close, in a "basic look" at the function.

If:

1.the screen and sediment composition is as you propose in your current design,
2.the plenum void space is also the same,

then the shown diagram simply equates to replacing the manifold with a tap, right ?

Yes, the diagram replaces the manifold with a tap, and that does not represent a problem in itself, BUT, it is not that SIMPLE.

I'm trying to get my head around how adding a manifold improves the dynamics of waste extraction and can't quite grasp it at this moment. Am I missing something fundamental ?

Yes, It is not the manifold itself that is important here, it is that the manifold was designed with a "restriction" that is created by the total area of the holes, relative to the area of the plenum piping I.D..

If you will review the previous post carefully, you will see that I explained how this restriction could be designed into the system that you offered, and that it could be made to work in this way.

It could possibly, even be a better design, in the end, IF restriction is utilized with high flow, and short duration, to achieve "flow balancing". Else-wise, "channeling" will occur, and "control" over the bacteria populations will be lost.

I hope this helps, I'm still trying to keep up with the bacteria discussion that got "dropped", from a few posts ago.

> barryhc :beachbum: :wavehand:

[barryhc]

ReefClown, I have finally gotten around to reviewing your information on "bio-film thicknesss".

Originally posted by reefclown
The thread appears to be evaluating a method of controlling bacterial activity within a sediment layer. And the core of the discussion looks at the effects of bacterial activity within that sediment under varying circumstances.

I was simply meaning to ask what activity you believe occurs at a smaller scale, for example on the bacterial film that coats a single grain of sand. Is this bacterial film capable of completing the full nitrogen cycle. i.e does the bacterial film covering the grain of sand contain aerobic, anoxic and anaerobic zones/bacteria within it?


Quote, from your link:The result of microelectrode measurements showed that a high sulfate-reducing activity was found in a narrow anaerobic zone located about 150 to 300 µm below the biofilm surface and above which an intensive sulfide oxidation zone was found. The biogeochemical measurements showed that elemental sulfur (S0) was an important intermediate of the sulfide reoxidation in such thin wastewater biofilms (approximately 1,500 µm), which accounted for about 75% of the total S pool in the biofilm.?

>> 1,500 µm is 1.5mm which is 1/16". ( "thin wastewater bio-films" )

Quote, from your link:Therefore, successive vertical zonations of predominant respiratory processes occurring simultaneously in close proximity have been found in aerobic wastewater biofilms with a typical thickness of only a few millimeters

>> A "few millimeters" = 3mm = 1/8". ( typical thickness )

Quote, from your link:Composite DIC image of the entire biofilm vertical section (scale bar = 200 µm). The biofilm thickness is about 1,500 µm.

>> Again, 1,500 µm is 1.5mm which is 1/16".

I did not think that you were questioning my understanding of distances, I was questioning yours.

I'm simply asking you to consider a lower denominator, as it may aid in the understanding of how the sediment will operate when the oxygen gradient changes.

so in effect rather than the 1000 microns you mentioned earlier a more realistic target figure MAY be in the range 10-300 microns ? everything below 300 microns being anaerobic. Add degradable organic matter to the above equation and the nitrifying layer will reduce yet further?

If we can come to some agreeable understanding of various bio-film thicknesses, then we might be able to make some progress on bacterial population discussions. I am looking forward to it.

Let's start. I think that the point that is being made, about the bio-film, is that the surface of the "bio-film" is aerobic to begin with, such as would be the case, where algae on a surface, feed nutrients to the aerobic bacteria at the surface of the bio-film, which nutrients are then processed by the aerobic bacteria, into "food-stuffs" for the bacterialogical populations that are "deeper in" the bio-film.

I think that this MAY BE more predominant, in thicker bio-films, that are being fed with "solids", and less likely in "thinner populations that recieve their food from dissolved nutrients. Especially so, where these bacteria live in a "zone", that is not entirely "stagnant".

I don't believe in allowing detritus, fish poop, etc. , to collect at the substrate surface, and it does not occur in my current tank. So, I have not been looking at this system having to deal with high loads of undissolved solids, but more on the basis of dissolved nutrients, that are "common" to the water column, as a whole.

I think in terms of the "lower denominator", I have been thinking in terms of bacterial "films", if you like, that are as thin as 5 microns, or 5 µm, in the "Aerobic" upper layer of the substrate. I suspect that these "upper bacterial populations" would remain "thinner", because the water is not being allowed to become stagnant. This would only be true, of course, for the "High Frequency" type of plenum wasting.

I further suspect, that these "films" could become somewhat thicker, deeper in the bed, in the "Anaerobic zone" ( below 1-2" ) because "upward diffusion" is probably less predominant in this area, and is partially responsible for the "sinking" that is so commonly referred to in "DSB discussions".

How is that for a "restart" on bacterial discussion?

> barryhc :beachbum:

[barryhc]

Ok, for those who might "pop-in" here, and can't deal with reading the whole thread, which is getting lengthy, and for any who might have forgotten the emphasis of this endeavor, I am including an excerpt from another discussion, that offers a reasonably short summary, of at least my own objectives.

Here you go.

quote:
--------------------------------------------------------------------------------
The idea of a biofilm protecting the anaerobes is an intriguing one--but if these are strict anaerobes, to which oxygen is toxic, the biofilm will gradually erode as the uppermost layers are exposed to oxygen and die and decay away. Of course if we are dealing with "facultative anaerobes" this is not the case because these bacteria can live with or without oxygen. Being as no one has a great idea of what bacteria are at work here I would hesitate myself to make a statement about the effects of drawing oxygen through the "anoxic layer".
--------------------------------------------------------------------------------

I absolutely ABHORE the idea of drawing oxygenated water through the "Anoxic-zone" ( no oxygen ). In fact, if oxygenated water is drawn through the "no-oxygen" zone, then it isn't "Anoxic" anymore, is it? Sounds like a bad idea.

quote:
--------------------------------------------------------------------------------
And if you have some sand stirrers they will perform this job sufficiently.
--------------------------------------------------------------------------------

Good idea, I agree.

quote:
--------------------------------------------------------------------------------
Another thing to consider--in all of these proposed systems there is live rock being incorporated, am I correct? In that case, you really can't measure the actual effects of drawing water through the sand bed because in essence the LR is performing the same function. If the sytem works, is it because of or in spite of the plenum wasting? The only way to know for sure is to include no rock in the system at all.
--------------------------------------------------------------------------------

I don't think that is true. In my particular case, the plenum was installed about 5 mos. ago, but I have not drawn any water from it yet. My Nitrate has varied from as high as 80ppm down to 1ppm, but is now at about 5ppm. Phosphate has been as low as .5ppm, but is now at 1.5ppm. I have kept a rather steady ( and high ) bio-load for several months now.

If the "wasting" is able to improve Nitrate processing over a "standard plenum", then that effect will be observed over a period of time, by checking Nitrate in the "water column", after wasting begins, and continues.

Phosphate export is "almost guaranteed" to occur ( or be monitored )by way of it's presence in "the effluent".

Unlike ammonia which can ultimately be converted to gas which bubbles off, phospates can only be incorporated into the bacteria. Ultimately the DSB acts as a sink for phosphates, sulfur containing compounds and heavy metals. This is thought what acts to ultimately cause DSB's to crash. The sink gets full and starts to leak nutrients back into the water column.

Exactamundo!!!!!! . . . . unless the"sink" has a "drain"! :thumbsup:

Ok, now a dumb question--if we know phosphates can be processed in a fuge with macro, and we know DSB works well on its own processing nitrogenous wastes, at least for a time, why bother with plenum wasting?

While I agree, that Phosphate will be "bound" in a refugium, for subsequent removal by harvesting and/or pruning, that does not stop phosphate from being processed in the substrate also.

The primary reason for plenum wasting, is to "avoid the crash". The secondary reason for plenum wasting is to achieve improved Nitrate processing.

>>
>>>>The reason for having substrate, is "FOR THE CRITTERS THAT REQUIRE IT!!! . . . . NOT for "processing ". :hammer:
>>

I hope this is helpful, > barryhc

:beachbum:

["Umm, fish?"]

Another thing to consider--in all of these proposed systems there is live rock being incorporated, am I correct? In that case, you really can't measure the actual effects of drawing water through the sand bed because in essence the LR is performing the same function. If the sytem works, is it because of or in spite of the plenum wasting? The only way to know for sure is to include no rock in the system at all.

I think that it's pretty unlikely that the stuff that gets deep into a deep sand bed will ever get out again. I can imagine some of it being pushed back out with the nitrogen bubbles, but not much. And I don't imagine that the bacteria do a lot of traveling between strata. So, unless there are some sand stirrers that are really pushing stuff around, I would think the live rock has a pretty minimal effect on processing anything that's managed to make its way all the way down to the manifold.

So, by testing the water you wind up pulling out from down there, you ought to have a pretty good idea of what frequent wasting is doing for you.

And as for me, the less frequent waster, I always expect the water will be disgusting.... :)

[Obi-dad]

I still think having a drain with a DSB is way more complicated than having a drain with an SSB - and having the DSB external to the display (such as in fuge or even Calfo-style bucket), or even not having a DSB at all if you have sufficient live rock to do all the denitrification.

I am not bashing anyones' attempts to get a drain to work with DSB, just remarking that it gets very complicated trying to maintain the anaerobic layer, and worrying about how much, how often, whether you are hurting the anaerobes, etc. IMO, much easier to keep the DSB external (or not use one), and use the drain on the SSB to keep it from filling with gunk.

If you keep the DSB external, you don't have to worry about your display crashing, and can change the DSB out easily.

["Umm, fish?"]

Ok, now a dumb question--if we know phosphates can be processed in a fuge with macro, and we know DSB works well on its own processing nitrogenous wastes, at least for a time, why bother with plenum wasting?

A refugium can only bind the phos that gets to it. That is, the phos has to be in the water column. I will of course be running a 'fuge and will be trying other strategies to attempt to make sure that detrius stays in the water column as long as possible. But what we're trying to accomplish here is to figure out a way to get rid of the phos that gets stuck in the sand bed.

["Umm, fish?"]

If you keep the DSB external, you don't have to worry about your display crashing, and can change the DSB out easily.

This is true, but a lot of us would like to keep animals that need deep beds. And if you need a deep bed, it just makes sense to try to come up with a strategy that will try to keep the bed healthy for the long term.

We're really planning here for the post-4 to 5 year mark where it's said that some sand beds have trouble. I don't want that to happen to me. So I'm trying to plan for it....

[barryhc]

Originally posted by Obi-dad
I still think having a drain with a DSB is way more complicated than having a drain with an SSB - and having the DSB external to the display (such as in fuge or even Calfo-style bucket), or even not having a DSB at all if you have sufficient live rock to do all the denitrification.

I am not bashing anyones' attempts to get a drain to work with DSB, just remarking that it gets very complicated trying to maintain the anaerobic layer, and worrying about how much, how often, whether you are hurting the anaerobes, etc. IMO, much easier to keep the DSB external (or not use one), and use the drain on the SSB to keep it from filling with gunk.

Complicated "my foot"!!

"Fish", in as much as you insist on being a "lowly" infrequent flyer . . er . . . waster . . . er, well, whatever, You are obviously a man after my own heart. :lol: :lol:

Thanks, so much. > barryhc :beachbum:

["Umm, fish?"]

Complicated "my foot"!!

Yeah, I'd say the siphon is a pretty proven technology. At least, MY siphon is pretty proven. Sigh. I'm raising some FW fry and the daily 50% WC is wearing me out.

Thanks for the love. I'm in work hell and really procrastinating at the moment....

[barryhc]

Hell, I'm in "work heaven", are you looking for a career change? :lol:

> barryhc :beachbum:

["Umm, fish?"]

Hell, I'm in "work heaven", are you looking for a career change?

> barryhc

No, this too shall pass. If I'd hire more employees then I could take more time off. But, if I hire more employees, then I'd have to pay them (they are all so unreasonable that way).

Actually, my only employees are myself and my lovely bride. She's sick today, so I'm putting out her fires, too. Sigh....

We're just about to the end of our busy season, though.

[barryhc]

I have myself and my son ( just recently with my son ), "wife" handles "paper" mostly at night or on weekends. Had a bunch of "gorrilas" years ago, gave up for a while on gorillas, and just ran by myself. Were "firing up" again now with my son "on board", and were going to start with chimpanzees this time.

Gotta run. good night.

> barryhc :beachbum:

[reefclown]

Ok, now a dumb question--if we know phosphates can be processed in a fuge with macro, and we know DSB works well on its own processing nitrogenous wastes, at least for a time, why bother with plenum wasting?

Just for the sport of it:D

You can easily keep a system stocked with corals and few yards of fish using the proven methods, BB, DBS,e.tc. Now if the challenge was to continually up the fish stocking level to the capabilities of the system then some play is required.

The wasting plenum is just another idea to play with, sadistic maybe, but an idea to play with none the less:D

Just be kinda interesting to see what kinda mileage/flexibility it could provide in the handling of P and N.

I absolutely ABHORE the idea of drawing oxygenated water through the "Anoxic-zone" ( no oxygen ). In fact, if oxygenated water is drawn through the "no-oxygen" zone, then it isn't "Anoxic" anymore, is it? Sounds like a bad idea.

I'm having a chilled eve, so not going to start thinking:bum:


But for when the neurons kick in, are you planning to control/alter the depth of all 3 sediment zones or just the aerobic and anaerobic.
Why play with 2, when there are 3?

[barryhc]

Originally posted by reefclown
Just for the sport of it:D

You can easily keep a system stocked with corals and few yards of fish using the proven methods, BB, DBS,e.tc. Now if the challenge was to continually up the fish stocking level to the capabilities of the system then some play is required.

The wasting plenum is just another idea to play with, sadistic maybe, but an idea to play with none the less:D

Just be kinda interesting to see what kinda mileage/flexibility it could provide in the handling of P and N.

Very good ReefClown, I couldn't have said it better. :thumbsup:

Of course, we don't want to forget the "nasties" that go "down the drain", instead of back up into the water column "eventually-maybe". ( The "forever-sand-bed"! )

But for when the neurons kick in, are you planning to control/alter the depth of all 3 sediment zones or just the aerobic and anaerobic.
Why play with 2, when there are 3?

Start on page 9, especially the post immediately prior to your first post, which discusses the three zones, and how they are "stretched". :p

Get those neurons "firing" again. > barryhc :beachbum:

[salty joe]

This is a good thread. I hope we can keep it going for years and years, because we're going to need to. Speaking of long threads, timewise that is, I wonder what the longest running thread that stayed active is on reef Central.? Thanks for all the interesting reading and links. I can hardly wait to see results from water that was drawn from the plenum. Thanks again.
Joe

["Umm, fish?"]

Hey barryhc! I wonder if I could ask your advice. I roughed out the manifold. I've just finished setting up my drill press. I'm ready to drill the siphon holes. What size holes do you think I should drill?

The tank is 4' x 2' - 4" or so in depth to make room for the overflows. The manifold is a basic rectangle, with crosses every 4.5" or so. That means I can only fit in a couple of holes per piece of pvc (in between the crosses). Thanks!

Andy