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View Full Version : Advice on New Sand...Possible Plenum?


JonezNReef
08/24/2016, 07:03 AM
I am planning on adding sand to my refugium, a deep sand bed(possibly a plenum) in my sump that isn't lite an serves as a cryptic zone and a shallow sand bed to my DT.
The question is will my tank cycle again from this? Is there anything I should watch out for? Should I use one size or multiple sizes of sand? Should I add all the substrate over a period of time?

I was planning on having different size substrate in my DSB starting with rock rubble, then crushed coral (calcium reactor media), then Fla crushed Coral, and finally Aragonite sand. I was wanting to do different size substrate layers to allow water to flow easily through the sand. I also was considering a plenum under the sand bed as well. I was wondering if anyone has any experience with a plenum at all and what the pros and cons where in your experience?
I have read about them and have read some of the pros and cons but would like to hear someones first had experience with one.
As for the the other sand beds I want a decent sand bed in the fuge for pods and what not. Also I want a shallow sand bed in the DT because I don't care for the look of a BB tank and it bothers me more than I thought it would. Ive liked how easy it is to clean without sand but think it will look better with it. Not sure if it would really serve a function other than looks though as far as my DT goes.

Please any and all thoughts,ideas and experience will be appreciated

Subsea
08/27/2016, 08:54 PM
Jaubert Plenum with DSB is differrent than DSB described by Ron Schmeck. The Jaubert Plenum relies on bacteria to perform denitrification. Use Caribsea Crushed Coral at 2mm-5mm in diameter. The Jaubert Plenum sandbed should be 4"-6" deep. With course substrate, oxygen penetrates deeper into substrate allowing more faculative bacteria to perform denitrification chemistry.

Dr Ron Schmeck's DSB is designed for nutrient recycling and is all about the worms and other detrivores. Sugar sand and special reef grade sand would be appropriate for this application.

Your concept of water flowing thru the sand will promote detritus settling between rock rubble. With enough detrivores, it may not be a problem, but I would not recommend it.

reef thief
08/27/2016, 09:04 PM
Iv'e never met anyone that stuck to a DSB for the long run. Give it a shot if your heart desires. To answer your cycle quetion. No. As long as youre only adding sand with no organic death in it. Just rinse it out and you'll be good to go.

Subsea
08/28/2016, 05:39 AM
I am planning on adding sand to my refugium, a deep sand bed(possibly a plenum) in my sump that isn't lite an serves as a cryptic zone and a shallow sand bed to my DT.
The question is will my tank cycle again from this? Is there anything I should watch out for? Should I use one size or multiple sizes of sand? Should I add all the substrate over a period of time?

I was planning on having different size substrate in my DSB starting with rock rubble, then crushed coral (calcium reactor media), then Fla crushed Coral, and finally Aragonite sand. I was wanting to do different size substrate layers to allow water to flow easily through the sand. I also was considering a plenum under the sand bed as well. I was wondering if anyone has any experience with a plenum at all and what the pros and cons where in your experience?
I have read about them and have read some of the pros and cons but would like to hear someones first had experience with one.
As for the the other sand beds I want a decent sand bed in the fuge for pods and what not. Also I want a shallow sand bed in the DT because I don't care for the look of a BB tank and it bothers me more than I thought it would. Ive liked how easy it is to clean without sand but think it will look better with it. Not sure if it would really serve a function other than looks though as far as my DT goes.

Please any and all thoughts,ideas and experience will be appreciated

To answe the post by Reef Thief, I have maintained a Jaubert Plenum 75G mixed garden on top with a 30G ecosystem mud filter refugium on bottom for more than 10 years.

What are your goals for making these changes? What was your biological filtration with a bb tank and sump? What is in the display tank? Do you skim?

JonezNReef
08/29/2016, 11:27 AM
First thank you guys for your replies.
As far as it goes I have been sketchy about DSB for a while and that is only because of not understanding and researching on my own when I started my first saltwater tank. When I first started this hobby I was misled by a LFS and told to do a DSB with playground sand and seed it with 10lbs or so of Live Sand to save money on buying all live sand. Of course this led to that tank crashing do to the overload of silica from the playground sand. Now hear we are 5 years and 3 or 4 tanks later and I have learned and continue to learn more and more.

To answer Patrick, my goals are many. I know that we can never fully emulate the ocean 100% but I would like to do the best I can to give my saltwater prisoners the closet life to it I can. I went BB on my 180 because I knew that its easier to add sand than it is to remove it. Also BB is much easier to clean all of the uneaten fish food, detritus, and unwanted junk from the tank. (Which this is what I thought I was suppose to do but now think other wise.) Since I went with a BB DT I have about 150lbs of LR rubble in the sump, about 20lbs in the above tank refugium, and about another 100lb of LR in the DT its self. It houses a Yellow Tang, a Scopas Tang, a clown fish, and 3 blue chromis with a mix of LPS, SPS, NPS, and softies(mostly frags) and a few snails and hermit crabs. I do skim with a DIY 5 gallon bucket skimmer and I also have a DIY waterfall ATS. Thats about it...no mechanical, media, reactors, or controllers.

With all that said I have been reading and following a lot of threads on many different opinions on ways to keep fish and coral. A few of the post being yours. After reading and researching I decided to give certain ideas a try. First I took out my filter socks completely so I would have one less death trap for pods. I noticed a favorable change in the tank after this. Then I went from wet skimming to light dry skimming which basically makes my skimmer and overpowered bubbler for gas exchange. Once again after I did this I noticed, that while there was a little more detritus in the tank, some coral started growing a little faster and had better PE than it had previously. Also since I did those 2 simple thing I noticed that the micro life in my tank has exploded. My above tank refugium's glass is covered in pods and also the DT has a lot more as well.

So my goal for wanting to do this is to hopefully create a better ecosystem in my glass box to make it more natural over all as far as nutrient recycling and diversity of life. I was wanting to do different size substrate in hopes that if I did do a plenum it wouldn't go full anaerobic on me and start producing hydrogen sulfide. I was hoping that if i started with rock rubble and the layered each size substrate over the one before then water could flow through to the plenum easier. The top most layer would be a thinner layer of fine sand to hopefully keep detritus from accumulating while with each layer getting more course until it reaches rock rubble size at the bottom which would hopefully allow water with oxygen to pass through. This I would have located in my sump which isn't lite and also serves as a "cryptic zone". I wanted to do the same concept of layering the substrate in my refugium but without a plenum underneath and probably not as deep. That or I might go with Marical Mud in the refugium instead...I'm still up in the air on this choice. And as far as sand in the DT, I just want it in there to appeal to my eye a little more.

This is a never ending work in progress as far as changing my system here and there to see what "Works for ME" and what doesn't. I try to keep thing as simple as I can and would love for my tank to be as "natural" as it can too.

Subsea
08/30/2016, 02:19 PM
I applaud your approach to making one change at a time, to evaluate it. It really sounds like your system is firing on all cylinders.

The Jaubert Plenum DSB is designed for denitrification using reducing chemistry and faculative bacteria to export free nitrogen gas. To that goal, only one size substrate is required. Diffusion, polarity of water molecules and convection all work to move water thru sand grains. In my Jaubert Plenum of ten years, I often see a thin hydrogen sulfide line migrating up and down. Sometimes, when I stirred the top inch, I would even smell h2s. The human nose can smell h2s at 10 parts per billion. This is not enough to hurt anything. In fact, I say that sulfur is an important nutrient in phytoplankton and macro. With phytoplankton at the bottom of the food chain, everything that consumes phytoplankton consumes sulfur. In the chemical analysis of red Ogo seaweed, sulfur concentration was at 4.81% which was twice the concentration of nitrogen and was only exceeded by potassium at 13.54%.

The physics of putting larger substrate on bottom with smallest on top will not work. The fine sand will migrate to the bottom, resulting in a mixed aggragate, which IMO, serves no purpose.

JonezNReef
08/30/2016, 03:14 PM
Makes since! I didn't think about the smaller sand settling into the larger substrate. And that is very interesting that your algae analysis came back with reading like that. I never would have guess that algae would have such a high level of sulfur and potassium. Especially when K+ is .0102 mol/kg and SO2-4 is .0282 mol/kg in NSW. With that said, I am a little less wiry of a plenum because, though I love the concept, I was scared of it nuking the tank.

So could a one benefit by adding a thin layer of crushed coral under it plenum? Ive read that the pH drops down in this area due to lack of oxygen and was wondering if I could use this to my advantage to break down the crushed coral adding small amounts of calcium, carbonate and trace elements. I mainly wondering if it could help with keeping trace elements up since I would like to do less water changes as time passes.

Also do you believe that MM would be better in a refugium or a DSB? I don't know anyone who has first hand experience with MM and Ive read mix reviews on it too. I am thinking of giving it a go regardless because it would kind of complete my system with yet another substrate that is naturally in the ocean. Plus its loaded with trace elements and could help with supporting my micro life.

reef thief
08/30/2016, 04:26 PM
MM sounds like it will be good in a tank like yours. Iv'e read that MM does not do good with SPS and will make your skimmer go nuts. If you can make your system balance out with MM and a skimmer let me know how you did it. Iv'e never used MM but have considered using it in a separate system with no SPS or skim. There are always ways to make these products work in your favor and you won't know unless you try.

JonezNReef
08/31/2016, 08:12 AM
I haven't read anything about MM not working well with SPS. I will have to look into this some more because I do have some SPS and would like some more in the future. Regardless I think I am going to give it a try. I am going to look into how much MM I need for it to be effective and go from there. One thing I'm wiry of with MM is running the lights on my fuge 24/7. I am going to look into everything a little more over the next couple weeks before I pull the trigger. Also I think I am going to give the plenum and DSB a try. I plan on doing this in my sump so if I don't like it I can easily take the sump offline and remove it.

JonezNReef
09/01/2016, 07:04 PM
According to MM it can be used in fish only, coral only and SPS systems. Also says that a skimmer isn't required. Not sure how well it will hold up to what it claims but I think I'm going to try it out. It's going to be a little pricey to start and it stinks you have to replace 50% yearly but I guess that helps prevent old tank syndrome.

After I get back from vacation I am going to get some and add it to my above tank refugium. Since you only need a 1" layer I might cover the bottom and then make a tray or two to hold another layer above it. After that I will probably wait to add a DSB with plenum to my sump depending on how the MM goes.

herring_fish
09/04/2016, 10:13 PM
http://asaherring.com/Reef/Sandsetup.jpg

http://asaherring.com/Reef/Sandsetup.pdf

This article was published many years ago but may be of some help, particularly the nuts and bolts of building a plenum sand bed. I wrote it in collaboration with Caribsea and was righting to sum up the prevailing theories of that moment. I re-typed the article so that it would work better on a web site. Unfortunately there are several typos so please excuse them.

There is some controversy over whether dissolution is a major factor or not but there are many people in each camp.

I used this type of sand bed for about 8 years before tearing it down when I moved. It work quite well. I used that and an algal turf scrubber and nothing else.

herring_fish
09/04/2016, 10:37 PM
I used critters in the top layer of sand. and did not find that I had a build up of detritus. Below is about the third re-posting of a few comments that were not in the article but my be of interest.

Quote:
Originally Posted by tmz View Post
It does release nutrients as it degrades from hydrolysis and microbial activity occurring in a cascade with each digestion reducing the nutrient value of the remaining detritus , ultimately leaving refractory mineralized remnants which are of little consequence. ....

I agree. This is a little anecdotal observation of mine from the past. I was talking about a jaubert style sand bed with open plenum bottom.


Quote:
Originally Posted by herring_fish
....I lowered the front of the bed so that it looked better against the front glass. Critters are suppose to inhabit the top, aerobic zone but nothing gets passed the two screens into the anaerobic zone and the stagnant zones.

I wanted to see into the plenum so before I installed anything, I encased a plasticized magnet in epoxy and placed it on the bottom piece of glass in the tank. The stand that I had, allowed me to look up through the bottom of the tank. In about a month a layer of detritus formed on the bottom glass. In a few months, I put another magnet up to the first one and was able to slowly and carefully drag it around through the sediment. I could see that it was very uniform at about 1/4 inch thick. I only did this one or two more times over 8 years or so. It wasn't too exciting.


When I tore the tank down, I was very careful, like a paleontologist. When I got through the sand beds I looked at the bottom sediment and there was that same depth of 1/4 inch of detritus that formed in the first few months.

It appeared to me that something processed this stuff. The screens are there to keep out critters and there weren't any dead skeletons, shells or any other forms of remains. This led me to think that the last vestiges of detritus must have been falling to the bottom slowly and bacteria was (...well not eating it but) processing it away. The ATS must have been the eventual vehicle for export of detritus byproducts that come from different stages of decomposition.

In nature, on dry land, fecal excrement is not the last stage of nutrient breakdown. Otherwise, we would be buried in it. It is broken down whether it is in the soil or sitting on the sidewalk. There is always something that lives off of what that last organism left behind. To some degree, this can be done inside of a closed reef system, although removal is far better where possible!!! Never the less, there is a complex food chain going up the latter before food enters a fish's gut. Likewise, there is a complex and little understood chain of organisms that process that food after it leaves the gut. "Dust to dust" and all that?....

.....I would think that whatever is deposited at the bottom was pretty close to inert....