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SomeDude12
10/07/2013, 02:06 PM
Is there any evidence, that biopellets can cause STN/RTN? I recently began running biopellets on my 210 that all inhabitants moved from my 150. Many of the acro colonies have grown from small frags to 4-8" colonies. I'm experiencing 50-75% of my acro's experiencing slow tissue necrosis. Many I've dipped numerous occasions with iodine, trimmed above the line and still experiencing the STN. Another odd scenario is that it tends to be centralized/affected on the right side of the tank.

I ran biopellets for 12+ months on my 92, with no problems (so I'm not new to the usage of them). Same brand pellets (BRS) and reactor. Any suggestions and input is greatly appreciated. I'm tempted to halt running pellets. I'm not sure if this is the culprit, but I'm loosing colonies that took years go grow!

Reefin' Dude
10/08/2013, 10:11 AM
why did you decide to start carbon dosing in the 210?

G~

bigevill1
10/08/2013, 12:31 PM
I have heard that the low nutrient environment from carbon dosing can make higher alk an issue with SPS. Something where your alk should be in the 7-9 range, not the 10-12 range some people keep. If your alk is high try bringing it down. I have also found that dosing amino acids helps SPS and LPS when running any form of carbon dosing. Coral has to eat, and some PO4 and NO3 is needed to keep them happy.

Reefin' Dude
10/08/2013, 12:48 PM
this is because the bacteria in the water column are now using up the free access elemental C produced by the biopellet reactor instead of using the elemental C from carbonate.

high alk is a real problem with SPS. when there is a large cesspool (read substrate) in the tank, the bacteria trying like crazy to use up the P in the substrate are using up a ton of carbonate. we associate this low alk with coral growth, but it is from the bacterial activity. when elemental carbon dosing the alk level tested is more accurate. the bacteria are not going to want to use the carbonate, and will use the free elemental C leaving more alk perceived for the coral. the higher the carbonate the more it gums up the photosynthesis pump, making it harder for the corals to perform photosynthesis. to much alk gets in the way of the formation of CO2.

unfortunately, due to the fact that we have not understood this relationship until recently and the fact that we had been believing that substrates were good, we are stuck with high alk salts as the norm instead of the exception. it is getting harder and harder to find properly balanced salts for those that want to run true oligotrophic systems. :(

G~

SomeDude12
10/09/2013, 08:41 AM
why did you decide to start carbon dosing in the 210?

G~

As intended, to minimize Nitrates.

I have heard that the low nutrient environment from carbon dosing can make higher alk an issue with SPS. Something where your alk should be in the 7-9 range, not the 10-12 range some people keep. If your alk is high try bringing it down. I have also found that dosing amino acids helps SPS and LPS when running any form of carbon dosing. Coral has to eat, and some PO4 and NO3 is needed to keep them happy.

Alkalinity, last checked on the 18th of Sept, tested at 9.016 dkh. Calcium 460/470 & 10ppm Nitrates. Ultimately, I decided to utilize equipment I already had and considering this tank has a high bioload, it was a good idea. The lack of nutrients (nitrates and phos), is highly unlikely. Where my 92 was unable to support the growth of any macroalgae, the 210, has no problems. In reality, I'm dealing with higher Phosphates, then ideal.

Reefin' Dude
10/09/2013, 02:49 PM
those levels are still very high over NSW levels. i have found no reason to use a Ca reactor on a tank that had 7 clams, 2 that were greater than 6" and plenty of SPS colonies and frags to cover the LR. i was able to maintain NSW levels with just a 5-10g water change a week and kalk in the top off. this was on a 125g tank.

bacteria are both our tanks greatest asset and its greatest liability. we do not want to think of all of the bacteria as a "single" organism, but like any organism, the bigger it is the more resources it uses up and the more waste it produces.

a high bioload of non-hermatypic organisms would not strip the water column of alk and Ca. a high bioload of bacteria on the other hand will strip a system of alk in a hurry in the search for elemental carbon.

G~

SantaMonica
10/09/2013, 07:06 PM
I too have heard of strong pellets/vodka/etc hurting corals. Slows down scrubbers, too.

Reefin' Dude
10/10/2013, 07:41 AM
of course. it switches the balance of power in nutrient uptake from the silly scrubber to the water borne bacteria. this is why carbon dosing "works".

G~

jda
10/10/2013, 02:32 PM
Evidence? No. You won't find much of this in a hobby. Anecdotes and experiences? Sure. You can drive N and P too low, or down too quickly to cause SPS to STN and/or RTN.

I am a substrate user, have no detectable N or P in any of my heavily stocked SPS tanks since the late 1990s and I let the bacteria in the sand come to equilibrium on their own to hand the nitrate and process the phosphate naturally. I have never used a carbon source on my reefs (loved it on a FOWLR that I had) and I have had "clear" results on Saliftert test kits since they first came out. My N and P are low enough that I have to watch my alk getting above 8, or my SPS can lose color - I am on Tropic Marin Pro Reef at 5.5-6.0 alk salt without even dosing a single drop of carbon.

There are a bunch of different way to skin this cat. Any of them will work pretty well if you have a good plan and are committed and GO SLOW. Carbon dosing is very effective and puts the equilibrium on you - natural bacteria based puts the equilibrium in the tank. If you are committed, then stick with it, but perhaps slow down. It might not hurt to cut back a bit on your feedings - going with less messy food like NLS pellets and not so much frozen might really help for a while.

rfequity
10/24/2013, 07:55 AM
Just want to chime in that bio-pellets almost killed all of my SPS. Started using them in June with a very slow ramp up process. Recently I noticed that all SPS was doing poorly. Even my monti caps were turning very pale. My nitrates are at 10PPM so I decided to go back to the old fashion way of WC to keep things in check. Within a week of unplugging the bio pellet reactor, the color is returning. Maybe it works for some, it sure did not for me.

Reefin' Dude
10/24/2013, 08:00 AM
there maybe more than one way to skin a cat, but the point is still to skin the cat.

the skinned cat in our case is nutrient removal. if nutrients are not removed as quickly as they are coming in, than the system is becoming eutrophic, the cat is still growing fur. the unfortunate part is one group understands this, the other does not and still keeps sweeping the nutrients under the rug(sand) and pretending that the cat is skinned.

G~

acesq
10/25/2013, 12:32 PM
there maybe more than one way to skin a cat, but the point is still to skin the cat.

the skinned cat in our case is nutrient removal. if nutrients are not removed as quickly as they are coming in, than the system is becoming eutrophic, the cat is still growing fur. the unfortunate part is one group understands this, the other does not and still keeps sweeping the nutrients under the rug(sand) and pretending that the cat is skinned.

G~

Reefin' Dude: what are the best practices for nutrient removal in a closed system intended for SPS? BB and carbon dosing? Shallow sand bed and carbon dosing? I certainly understand and agree with your posts on the subject here and in other threads, I just want to fine tune my systems. I've been running a 120 for three years with a shallow sand bed that I vacuum every two weeks along with a 15% water change and use a biopellet reactor for carbon dosing. I've not had many issues with anything other than a little Cyano that comes and goes, although I now feel that the sand has backed up with P and is causing a little algae outbreak along with the cyano. Time to change the sand. I have a new build starting and I'm trying to decide whether to epoxy a thin layer of sand on the bottom just for aesthetics (don't like the BB look) and stick with the biopellets or ???

Reefin' Dude
10/25/2013, 01:44 PM
lots and lots of flow. :D i made nutrient export a top priority in my last system. had a sand embedded epoxy bottom with the bottom coarse of LR also embedded into the bottom. there was not any LR sitting on the bottom. flow was able to get to the entire bottom. i had over 12,500gph of flow in my 125. here (http://www.thereeftank.com/forums/f6/the-rebuild-begins-63881.html?highlight=rebuild+begins) is a link to the build thread.

what i will do differently in my next build is move more water through the skimmer. i think skimmers nowadays are wimpy. they are efficient, but they just are not moving enough water through them. i hope to move close to 10x water through my skimmer, with a UV just in front of the skimmer that can handle that amount of flow also. i also plan on putting in a conical settling tank that can match this flow rate. plumbed immediately after the overflow and before the UV and skimmer. i had a 30g ready go, but i had to take down my tank before plumbing it in. i will probably need at least a 60g one for the next build. a conical settling tank will settle out all detritus into a single area. to make it better a valve on the bottom of the cone is used to drain water for a water change along with the removal of all detritus accumulated since the last water change.

i think carbon dosing can be useful, but only in a specific set of circumstances. there is so much micro food being put into the tank that water borne bacteria are the ones creating the inorganic nutrients. i do not think that carbon dosing should be used on tanks where the majority of the inorganic P and N are created by detritus/surface dwelling bacteria. i think in these cases the balance of carbon power is pushed away from the bacteria that are really doing the most amount of good, and feeding the bacteria that are doing the masking of the affects allowing more inorganic P to bind to the calcium carbonate structures.

G~

acesq
10/25/2013, 04:55 PM
I certainly agree with taking the detritus out of the tank before it has a chance to settle and decay. However, I'm not sure I understand this:

i do not think that carbon dosing should be used on tanks where the majority of the inorganic P and N are created by detritus/surface dwelling bacteria. i think in these cases the balance of carbon power is pushed away from the bacteria that are really doing the most amount of good, and feeding the bacteria that are doing the masking of the affects allowing more inorganic P to bind to the calcium carbonate structures.

What tanks have the majority of inorganic P and N created by other than detritus/surface dwelling bacteria?

The balance of power thing really has me stumped. Can you explain your take on the process that allows one group of bacteria sited on a biopellet to mask the effects of inorganic P binding and to take power from bacteria sited elsewhere (which would be sand and rock and to a much lesser extent in the water column)?
Art

Reefin' Dude
10/25/2013, 05:12 PM
What tanks have the majority of inorganic P and N created by other than detritus/surface dwelling bacteria?

very few. that is true. systems where detritus is heavily skimmed off or siphoned out in a timely manner will have very little detritus to supply inorganic N and P. a well designed true BB system will come very close.

The balance of power thing really has me stumped. Can you explain your take on the process that allows one group of bacteria sited on a biopellet to mask the effects of inorganic P binding and to take power from bacteria sited elsewhere (which would be sand and rock and to a much lesser extent in the water column)?
Art

it is how carbon dosing works. it provides the bacteria in the water column easy access to a carbon source, so that they can use up any available inorganic N and P. these bacteria are then skimmed off as a nutrient export. it is this bacterial activity that provides the nice low inorganic N and P levels people see when carbon dosing. providing the water borne bacteria all of the resources they need, starves the bacteria on the calcium carbonate surfaces. allowing the calcium carbonate to be in charge, doing what it does best. absorb phosphates. without an easy available elemental C for bacteria to use, they can not cleave the P off of the calcium carbonate. even though the water tests really well, the total system is still becoming more eutrophic. the calcium carbonate is just getting more and more full of P. how many people have you heard that have algae problems when they stop carbon dosing? ever wonder why? ;)

bacteria need resources. we all focus on the nitrogenous compounds, but like any life, they also need elemental P, C, and O.

G~

MisterP
11/03/2013, 08:43 AM
Reefindude----I'm with you on most of this but I'm kind of confused on the way the last post reads.

When you say "allowing the calcium carbonate to be in charge, doing what it does best. absorb phosphates." This is a good thing right?

Also when saying "even though the water tests really well, the total system is still becoming more eutrophic. the calcium carbonate is just getting more and more full of P." This is still a good thing right..the way it reads to me this is not so great but the other comment above seems to read contradictory to me.

I guess my confusion lies in the fact I thought the goal was to dose C to allow the bacteria to process more N and P in the specific ratio that C, N and P exist with C and N being the limiting factor for removing P, thus some folks may dose C and N in order to process more P. If this P is bound to the rock and substrate...Would this be good or bad?

If it is bound in the substrate would it just be easier to scoop out some small amount of substrate every week and replace it with fresh non-P bound substrate?

What happens when the P is bound in rock...obviously rock cant just be replaced like substrate. Are bacteria in the water column still able to "unbind" (if thats even a word) P?

dkeller_nc
11/03/2013, 10:24 AM
SomeDude12 - Not sure if you're still reading this thread, but here are a couple of thoughts on biopellets.

"Biopellets" are polysaccharides. The source of polysaccharide varies - there are various mixtures of alginate, guar gum, dextran and even corn starch. But fundamentally, they are all polymerized sugars. In the presence of certain bacterial enzymes and also through abiotic mechanisms, the bonds between these sugars are cleaved and the individual (sugar) monomers are dissolved in solution.

Various forms of "Carbon dosing" tend to be lumped into a catch-all phrase, but it's incorrect from a chemistry and biochemistry standpoint to think of the typical sources of organic carbon added to seawater as being completely equivalent. It is true that ultimately, it doesn't really matter what species or range of species of bacteria are being growth-promoted in the system with regard to consumption of carbon, nitrate and phosphate; they all require and therefore consume these elements in rough proportion to the Redfield ratio.

However, there is at least one scientific study that suggests that the type of carbon dosed does indeed have different affects on coral. Whether this is the influence of the actual molecular species of carbon or the types of bacterial species that are produced is unclear. Neverthless, this study did find that dosing of various sugars and polysaccharides was associated with mortality in several species of interest to aquarists in a roughly 3 week time frame. The authors noted that the pathology proceeded by tissue-edge necrosis - it could be argued that this is a description of STN.

To my knowledge, this type of study has not been conducted with the two other typical sources of carbon dosing: acetic acid (vinegar) and ethanol (vodka).

Controlling the free sugar concentration in solution with a biopellet reactor is very difficult since there is an overwhelming reservoir of the source polysaccharide, and the rate of dissolution depends on many factors that are also difficult to control. It's clear from net forums that many people run biopellets very successfully, but there are also a lot of anecdotal reports of serious issues.

Given this knowledge and at least the suggestion of serious coral mortality associated with high saccharide concentrations in seawater, I would not personally run biopellets in my reef tanks. It's just far too easy to dose vinegar or (less preferably) ethanol, and it's really easy to control the dose exactly.

lanshark
11/03/2013, 11:36 AM
To be honest guys, i was hopeful as i began reading this thread of learning something to improve the odds of keeping a sustained SPS tank. Unfortunately, the take away for me is for 98 out of 100 who attempt SPS will not succeed long term. We need solutions and proven techniques. Impressive vocabularies though... As RC is suppose to be an open discussion forum, the chemists like yourselves need to put the hard truth out there as they know it, closed systems cannot support SPS animals long term for the vast majority of hobbiests .... Jus my opinion... BTW, I am starting new build and not giving up just yet....

dkeller_nc
11/03/2013, 08:41 PM
Hmm - I wouldn't necessarily conclude that, at least that percentage of failure. If you peruse the SPS forum, there's lots of folks that have SPS tanks that are quite successful, and at least in my opinion, it's not particularly difficult.

What you'll want to consider as well is that reading forum posts heavily skews an impression towards "lots of problems" simply because people post when they have issues, but don't necessarily post "success".

I guess it also depends on what you mean by "long term", but there are quite a number of species/strains of acropora, montipora, and other SPS corals that have been in the hobby for 10 to 15 years or more, and that wouldn't really be possible if most people failed to keep these corals alive and healthy.

SantaMonica
11/04/2013, 07:59 AM
"even though the water tests really well, the total system is still becoming more eutrophic. the calcium carbonate is just getting more and more full of P." This is still a good thing right.

No. Rock will fill up in about a year, and you are back to problems.

C and N being the limiting factor for removing P

C is limiting; not N. DOC would be much higher, but bacteria eat it faster than it can accumulate. There is plenty of N in the water even when it tests zero; Urea alone is a constant from the fish; that's why your glass will always will need cleaning. Urea is such small particle size that it has large surface area and is broken down by bacteria immediately.

If it is bound in the substrate would it just be easier to scoop out some small amount of substrate every week and replace it with fresh non-P bound substrate?

This is not very efficient. Plus you lose the life in the sand. Just cultivate some algae to remove the P. That's what algae does.

What happens when the P is bound in rock

Once it "fill up" you get more problem. The rock equalizes with the amount of P in the water. So, keep the P in the water as low as possible with high continuous export.

Reefin' Dude
11/04/2013, 01:58 PM
Reefindude----I'm with you on most of this but I'm kind of confused on the way the last post reads.

When you say "allowing the calcium carbonate to be in charge, doing what it does best. absorb phosphates." This is a good thing right?

it is what it is. it is good or bad depending on how well you understand the process. it is great that calcium carbonate absorbs phosphate, the bad is that the bacteria are able to release it from the calcium carbonate. if this were not the case, then there would not be any life on earth. if we use calcium carbonate like a phosphate sponge and replace it regularly, then all is good. if we expect that it can absorb phosphates till the end of time without them becoming free again, then we are asking for problems.

Also when saying "even though the water tests really well, the total system is still becoming more eutrophic. the calcium carbonate is just getting more and more full of P." This is still a good thing right..the way it reads to me this is not so great but the other comment above seems to read contradictory to me.

as long as one understands that it can only absorb or bound so much, then all is good. problems come from when people think that the calcium carbonate will make P go away somehow. there is a constant trading of P between the calcium carbonate and the bacteria as long as there are the needed resources for the bacteria to remove the P from the calcium carbonate matrix. what happens is that these resources become unavailable and all you are left with is a substrate full of phosphate bound calcium carbonate and dead bacterial mulm that is full of N and P.

I guess my confusion lies in the fact I thought the goal was to dose C to allow the bacteria to process more N and P in the specific ratio that C, N and P exist with C and N being the limiting factor for removing P, thus some folks may dose C and N in order to process more P. If this P is bound to the rock and substrate...Would this be good or bad?

it is a good thing if the ONLY source of P was the calcium carbonate. it is not in our systems. we have waste products from the basic biological functions of all of the organisms in our system. this tends to be more accessible than the bound P to the calcium carbonate. the bacteria are going to go after the easiest available source of all of these resources.

P is going to bind to calcium carbonate no matter what. it is binding reaction. the removal of P requires a biological process and all of the resources needed for these processes.

If it is bound in the substrate would it just be easier to scoop out some small amount of substrate every week and replace it with fresh non-P bound substrate?

sure. that works well, and a lot of people do this. if a good source of low P substrate is found. P will bind to calcium carbonate, so more likely than not P will be there already. usually there is less with the new, than with the old.

What happens when the P is bound in rock...obviously rock cant just be replaced like substrate. Are bacteria in the water column still able to "unbind" (if thats even a word) P?

the bacteria in the LR are able to unbind the P from the calcium carbonate. life on Earth depends on this process. as long as there is enough flow around the LR to blow away any detrital buildup LR will self clean itself of phosphates. as long as the resources are available for the bacteria. flow is very important in this process. when "cooking" LR outside the tank it is important to swish the LR around in order to wash away any detritus that may be accumulation in some of the nooks and crannies of the LR.

--------------

algae does not remove as much P as people think. it converts inorganic P to organic P. P is not used that much as a building material, but an energy source. this is the big picture problem that is missed in this hobby and what makes algae an ineffective remover of P.

please read up on ATP, ATS and the phosphate reaction in living organisms. this is a fundamental of life. just because we can not test for organic P does not mean that it is not in the system. all we have to do is use our eyes. all of that "biomass" is an indicator that the system is full of organic P. it is still P. the more P the more eutrophic the system. just because the silly test kit (which can only read inorganic P) says zero does not mean that we have a low nutrient system. it can just mean that we have a ton of organic bound P that is using up the inorganic P as fast as it is being produced by other organically bound P organisms.

the best way to export P and N is to remove the waste products produced by the organisms that we want to keep. in other words. just clean up after your pet in a timely manner.

G~

jda
11/04/2013, 04:56 PM
Unfortunately, the take away for me is for 98 out of 100 who attempt SPS will not succeed long term.

I might caution you to not take what is said/posted on message boards as a critical mass of people in the hobby. Probably the 27 or 28 of the 30 most impressive reefers that I have met in just the Denver area do not post on any board, have no online presence and have no interest. I might suggest that you find some locally and reach out to them - the buy/sell forums are a great place to meet high end reefers - and study what they do... most of them have very simple systems with tons of patience and most use tech that is more than a few years old that is tried and true. Most have also gone years and years without a "crash" for any reason, but this is no accident. Actually, not much that they do is an accident.

MisterP
11/04/2013, 05:11 PM
Thanks all for the information. I guess the take away is cleanup after everything in a timely manner so P doesn't saturate all the calcium carbonate.

So in theory one could feed nice and heavy to satisfy livestock yet keep the inorganic P and N low by cleaning often, C dosing, GFO, GAC, etc?

dkeller_nc
11/05/2013, 08:59 AM
There are a couple of aspects of this discussion that aren't quite accurate from a biochemistry standpoint.

Phosphorus is indeed consumed by both algae and other living organisms in the ocean. The two biggest sinks for phosphate in living tissue is the cell wall, which among other things is composed of phospholipids and phosphorylated proteins, and DNA/RNA. So it is correct to think that algae, whether macro or micro, removes phosphate from the water as it grows.

However, there is a point at which the algae will cease growing or die back because there is insufficient inorganic phosphate in the water column. Precisely where this point is has not been well studied in marine species, but there is a possibility that the critical phosphate concentration in the water necessary to support algae growth is higher than desirable in a reef tank.

Calcium carbonate doesn't actually bind phosphate to a significant extent. Instead, calcium phosphate co-precipitates with calcium carbonate. However, the extent to which this occurs depends on the phosphate and calcium concentration in the water column, the pH, and the carbonate ion concentration. Generally speaking the binding of inorganic phosphates to reef rocks and/or aragonite sand is quite minor unless the inorganic phosphate concentration in the water is very, very high (well in excess of 5 ppm or more) or the pH is very, very high, such as would occur locally with a kalkwasser drip.

It is also not correct to think that bacterial processes that dissolve solid calcium phosphate are the major (or even minor) source of phosphate in the ocean. The vast majority of phosphate additions to the ocean ecosystem come from continental weathering of sedimentary rocks, with a rather vast amount of phosphate being recycled in the form of predation/consumption in the food chain. Removal of phosphate from the ocean ecosystem primarily occurs through deposition of dead algae (primarily phytoplankton) in the deep ocean, as well as a small contribution of dead animals and fecal matter precipitating as "marine snow".

Reefin' Dude
11/07/2013, 04:22 PM
There are a couple of aspects of this discussion that aren't quite accurate from a biochemistry standpoint.

Phosphorus is indeed consumed by both algae and other living organisms in the ocean. The two biggest sinks for phosphate in living tissue is the cell wall, which among other things is composed of phospholipids and phosphorylated proteins, and DNA/RNA. So it is correct to think that algae, whether macro or micro, removes phosphate from the water as it grows.

correct to the little amount of P that is involved in the cells. this P that is involved in the cells is transitory. that is where the confusion comes from, and why algae is a phosphate converter and not really a good phosphate exporter.

However, there is a point at which the algae will cease growing or die back because there is insufficient inorganic phosphate in the water column. Precisely where this point is has not been well studied in marine species, but there is a possibility that the critical phosphate concentration in the water necessary to support algae growth is higher than desirable in a reef tank.

we keep wanting to think of P as a building block. it is primarily an energy source in which all life on earth depends on. this is how cels get energy (https://www.ebiomedia.com/how-cells-obtain-energy.html). the conversion of P. ATP (http://en.wikipedia.org/wiki/Adenosine_triphosphate), ADP (http://en.wikipedia.org/wiki/Adenosine_diphosphate), and the Calvin cycle (http://en.wikipedia.org/wiki/Calvin_cycle#Calvin_Cycle). we need to stop looking at the water column. this is not helping our cause with figuring out this hobby. inorganic test kits are not accurate enough and they are not testing for anything of any real use. if there is algae, then there is sufficient inorganic P and N to support it.

Calcium carbonate doesn't actually bind phosphate to a significant extent. Instead, calcium phosphate co-precipitates with calcium carbonate. However, the extent to which this occurs depends on the phosphate and calcium concentration in the water column, the pH, and the carbonate ion concentration. Generally speaking the binding of inorganic phosphates to reef rocks and/or aragonite sand is quite minor unless the inorganic phosphate concentration in the water is very, very high (well in excess of 5 ppm or more) or the pH is very, very high, such as would occur locally with a kalkwasser drip.

calcium carbonate does a very good job at binding phosphates (http://www.reefcentral.com/forums/showthread.php?p=15968762). so well that it is used in kidney dialysis (http://www.ncbi.nlm.nih.gov/pubmed/3602677). if this study isn't telling, then i do not know what is (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2810262/?tool=pubmed).

"In this study, calcium carbonate was found to be an excellent phosphate binder, reducing up to 70% of the phosphates in a given sample of water, and it posed relatively negligent ecological repercussions."

this is exactly what a DSB is doing. why is it that only those in the SW hobby want to ignore this. :(

It is also not correct to think that bacterial processes that dissolve solid calcium phosphate are the major (or even minor) source of phosphate in the ocean. The vast majority of phosphate additions to the ocean ecosystem come from continental weathering of sedimentary rocks, with a rather vast amount of phosphate being recycled in the form of predation/consumption in the food chain. Removal of phosphate from the ocean ecosystem primarily occurs through deposition of dead algae (primarily phytoplankton) in the deep ocean, as well as a small contribution of dead animals and fecal matter precipitating as "marine snow".

the abyss. the "marine snow" has to go somewhere. though there is some seasonal nutrient upwelling that does occur around the world. the phosphate cycle.

http://www.thereeftank.com/gallery/files/2/0/5/0/phosphoruscycle.gif

G~

simonh
11/08/2013, 07:28 AM
calcium carbonate does a very good job at binding phosphates (http://www.reefcentral.com/forums/showthread.php?p=15968762). so well that it is used in kidney dialysis (http://www.ncbi.nlm.nih.gov/pubmed/3602677). if this study isn't telling, then i do not know what is (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2810262/?tool=pubmed).

"In this study, calcium carbonate was found to be an excellent phosphate binder, reducing up to 70% of the phosphates in a given sample of water, and it posed relatively negligent ecological repercussions."

this is exactly what a DSB is doing. why is it that only those in the SW hobby want to ignore this. :(


Extrapolating findings from kidney dialysis to a different matrix such as seawater is quite a leap IMO.

Reefin' Dude
11/08/2013, 07:41 AM
huh? the point is that calcium carbonate binds phosphates. the links i posted show that this occurs in many different media. whether it is in blood, or even in water. the fact is that calcium carbonate is a phosphate binder. that quote i posted above was not from the dialysis study, it was from this study:

Calcium Carbonate Phosphate Binding Ion Exchange Filtration and Accelerated Denitrification Improve Public Health Standards and Combat Eutrophication in Aquatic Ecosystems (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2810262/?tool=pubmed)

it is even listed as a phosphate binder when you look up phosphate binders (http://en.wikipedia.org/wiki/Phosphate_binder) on wikipedia.

i do not see how the links i posted do not confirm that calcium carbonate is a phosphate binder and we in the SW hobby industry seem to want to ignore this and spend insane amounts of money trying to fight this instead of working with it.

G~

MidwesternTexan
11/08/2013, 08:20 AM
huh? the point is that calcium carbonate binds phosphates. the links i posted show that this occurs in many different media. whether it is in blood, or even in water. the fact is that calcium carbonate is a phosphate binder. that quote i posted above was not from the dialysis study, it was from this study:

Calcium Carbonate Phosphate Binding Ion Exchange Filtration and Accelerated Denitrification Improve Public Health Standards and Combat Eutrophication in Aquatic Ecosystems (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2810262/?tool=pubmed)

it is even listed as a phosphate binder when you look up phosphate binders (http://en.wikipedia.org/wiki/Phosphate_binder) on wikipedia.

i do not see how the links i posted do not confirm that calcium carbonate is a phosphate binder and we in the SW hobby industry seem to want to ignore this and spend insane amounts of money trying to fight this instead of working with it.

G~

You mentioned DSB's.

Are you advocating we all use DSB's for Phosphate binding then?

Reefin' Dude
11/08/2013, 08:45 AM
not necessarily, but that is what they do. we need to know that calcium carbonate is a phosphate binder and adjust our maintenance according to this. there is nothing wrong with running a DSB. the problem is that the way we were told they "work" is not actually the way they "work". they are a phosphate sink. nothing more. we should treat them as such and maintain them as such.

we see people using GFO and Aluminum Oxide all of the time as phosphate binders, yet we do not see those phosphate binders used indefinitely. they get changed out periodically. the same should be done with calcium carbonate. we can get the same results running aragonite in a GFO reactor, and changing it when the aragonite gets full.

there are certain systems in which the DSB is the proper setup. more eutrophic systems will see long term results using a DSB with minimal maintenance. DSB's used in more oligotrophic systems have a finite life before the calcium carbonate has absorbed all it can. (this is a gradual process, it just does not just happen over night, but the amount of available inorganic P slowly increases). we just need to know the limitations of what the media we put in our system is and adjust accordingly.

if one wants to run a RDSB and replace it every year or so, then great. that is making the most use of the binding abilities of calcium carbonate, and not trying to have it do something that it can not.

there is nothing wrong with DSB's or substrates if the pro's and con's of each are known and maintenance is adjusted for these pro's and con's.

following the phosphate trail is not easy and can lead to a lot of long nights going down various knowledge rabbit holes. it is worth doing the legwork, but it can make your head spin at times. we want to think of it as static, it is far from static.

G~

MidwesternTexan
11/08/2013, 11:21 AM
And how does a finely crushed Coral bed instead of sand, ~ 1-2"'s play into that P binding?

RDSB? I haven't heard of that for years- Anthony Calvo was all into that for awhile- maybe he still is?

Reefin' Dude
11/08/2013, 12:20 PM
the smaller the grain size, the more P it can bind. surface area is increased. the smaller grain size makes a less permeable barrier between the substrate and the water column. allowing for a greater maximum P in the substrate. the larger the sand size the easier it is to clean, but needs to be cleaned more often.

there is a thread running around here that discussed RDSB's pretty heavily.

if you just think of a substrate as a phosphate sponge, then there are a whole lot of things that start falling into place with how we were told DSB's work and why they tended to show problems down the road.

G~

MidwesternTexan
11/08/2013, 12:52 PM
the smaller the grain size, the more P it can bind. surface area is increased. the smaller grain size makes a less permeable barrier between the substrate and the water column. allowing for a greater maximum P in the substrate. the larger the sand size the easier it is to clean, but needs to be cleaned more often.

there is a thread running around here that discussed RDSB's pretty heavily.

if you just think of a substrate as a phosphate sponge, then there are a whole lot of things that start falling into place with how we were told DSB's work and why they tended to show problems down the road.

G~

Precisely why I personally don't run anywhere near a DSB.
I'd say my CC averages about 1"- 1.5" average.
I do siphon it sometimes too with a WC, not everytime though.

Pcrain
11/09/2013, 07:22 PM
I do maintenance on around 30 reef tanks .. almost all these tanks have biopellets I see less coral loss then I did when biopellets did not exist I have heard of the horror stories of biopellets but my own experience dose not back it up

GroktheCube
11/09/2013, 09:29 PM
not necessarily, but that is what they do. we need to know that calcium carbonate is a phosphate binder and adjust our maintenance according to this. there is nothing wrong with running a DSB. the problem is that the way we were told they "work" is not actually the way they "work". they are a phosphate sink. nothing more. we should treat them as such and maintain them as such.

we see people using GFO and Aluminum Oxide all of the time as phosphate binders, yet we do not see those phosphate binders used indefinitely. they get changed out periodically. the same should be done with calcium carbonate. we can get the same results running aragonite in a GFO reactor, and changing it when the aragonite gets full.

there are certain systems in which the DSB is the proper setup. more eutrophic systems will see long term results using a DSB with minimal maintenance. DSB's used in more oligotrophic systems have a finite life before the calcium carbonate has absorbed all it can. (this is a gradual process, it just does not just happen over night, but the amount of available inorganic P slowly increases). we just need to know the limitations of what the media we put in our system is and adjust accordingly.

if one wants to run a RDSB and replace it every year or so, then great. that is making the most use of the binding abilities of calcium carbonate, and not trying to have it do something that it can not.

there is nothing wrong with DSB's or substrates if the pro's and con's of each are known and maintenance is adjusted for these pro's and con's.

following the phosphate trail is not easy and can lead to a lot of long nights going down various knowledge rabbit holes. it is worth doing the legwork, but it can make your head spin at times. we want to think of it as static, it is far from static.

G~

It is worth noting one major functional difference between LR/sand and GFO. Aragonite doesnt act as a P "magnet", rather it tends towards equilibrium with the water. In systems that don't have high concentrations of free phosphates, the issue of sand or rock "filling up" will never really present itself. However, if a system has a lot of free phosphate for a long period of time, one would be hard pressed to reduce it without replacing rock and sand.

GroktheCube
11/09/2013, 10:06 PM
To be honest guys, i was hopeful as i began reading this thread of learning something to improve the odds of keeping a sustained SPS tank. Unfortunately, the take away for me is for 98 out of 100 who attempt SPS will not succeed long term. We need solutions and proven techniques. Impressive vocabularies though... As RC is suppose to be an open discussion forum, the chemists like yourselves need to put the hard truth out there as they know it, closed systems cannot support SPS animals long term for the vast majority of hobbiests .... Jus my opinion... BTW, I am starting new build and not giving up just yet....

People tend to make it sound more difficult and complex than it is.

Most SPS require stable water chemistry, adequate water movement, adequate light, adequate nutrition, and reasonably clean water.

IME, many SPS corals are among the most hardy, least picky, and most bulletproof once established. My bird's nest is easily the fastest growing of my long term residents. Yesterday, I accidentally broke about 8 tips off of branches, and it had already grown back over and rounded off the broken edges by lights out tonight.

Most montis seem pretty indestructible. I have an M. mollis that was knocked onto a Galaxea when it was ~half dollar sized a few months ago. About 5 sq millimeters of tissue survived. Now, it is larger than it was when the incident occurred.

My Hydnophora is the only SPS I have that seems a bit finicky and slow growing. I recently moved it to a higher flow area, so we'll see if it's happier there.

Euphyllia are the corals that I can't keep happy for the life of me, and my Symphyllia is also pretty slow growing and touchy.

For whatever reason, my SPS always seem to be less offended by "minor" WQ issues, like application of aiptasia killing gunk near them, or a few hours with no flow, or a few days without 2 part, etc.

Reefin' Dude
11/10/2013, 04:18 PM
It is worth noting one major functional difference between LR/sand and GFO. Aragonite doesnt act as a P "magnet", rather it tends towards equilibrium with the water. In systems that don't have high concentrations of free phosphates, the issue of sand or rock "filling up" will never really present itself. However, if a system has a lot of free phosphate for a long period of time, one would be hard pressed to reduce it without replacing rock and sand.

aragonite does act like a P magnet. it is a phosphate binder. it doesn't tend towards equilibrium. if P is present and there is an open binding site on the calcium carbonate it will bind. once bound it will stay there until the matrix is dissolved or bacteria use it. it does get confusing because in our systems we are dealing with P both chemically and biologically. we want to think of them as one or the other, but they are different processes.

G~

GroktheCube
11/10/2013, 09:51 PM
aragonite does act like a P magnet. it is a phosphate binder. it doesn't tend towards equilibrium. if P is present and there is an open binding site on the calcium carbonate it will bind. once bound it will stay there until the matrix is dissolved or bacteria use it. it does get confusing because in our systems we are dealing with P both chemically and biologically. we want to think of them as one or the other, but they are different processes.

G~

This differs from my understanding based on what I've read from Randy (and other in hobby publications). His statements suggest that in our tanks, substantial release of phosphate from aragonite generally becomes an issue when phosphate concentration in the water remains elevated for a long time and then drops, or when a pH drop causes aragonite, and any phosphate precipitated onto it, to dissolve.

My understanding is that if one has consistently low phosphate levels, and steady pH, one is unlikely to experience much in the way of phosphate leaching back into the water. Is this incorrect?

Randy seems to state as much pretty explicitly in this post, and in other posts in this thread: http://www.reefcentral.com/forums/showpost.php?p=15968898&postcount=9

In other words, if one maintains low phosphate levels, the use of LR or aragonite sand does not present a long term problem. On the other hand, if one does not maintain low phosphate levels, having LR and aragonite sand can make reducing those levels rather difficult.

If I'm wrong on this, please correct me, but I did a couple quick searches and could not find anything that ran counter to my current understanding. Maybe I was a bit unclear in my original statement.

DiscusHeckel
11/11/2013, 07:26 AM
aragonite does act like a P magnet. it is a phosphate binder. it doesn't tend towards equilibrium. if P is present and there is an open binding site on the calcium carbonate it will bind. once bound it will stay there until the matrix is dissolved or bacteria use it. it does get confusing because in our systems we are dealing with P both chemically and biologically. we want to think of them as one or the other, but they are different processes.

G~

Hi G~ (Reefin' Dude),

Thanks for sharing your thoughts and expertise.

I am running my third reef tank, which is BB. In my previous two set ups and the early stages of my present tank, I used shallow aragonite sand bed (up to 1 " depth). Shortly after stocking with fish and corals, certain sections of my sand bed always solidified looking like a flat rock, which I was able to crumble with my hands, but sometimes I was not not able to do so. Was the solidification of the sand bed due to bacteria binding phosphates to calcium carbonate?

DH

Reefin' Dude
11/11/2013, 11:45 AM
This differs from my understanding based on what I've read from Randy (and other in hobby publications). His statements suggest that in our tanks, substantial release of phosphate from aragonite generally becomes an issue when phosphate concentration in the water remains elevated for a long time and then drops, or when a pH drop causes aragonite, and any phosphate precipitated onto it, to dissolve.

My understanding is that if one has consistently low phosphate levels, and steady pH, one is unlikely to experience much in the way of phosphate leaching back into the water. Is this incorrect?

Randy seems to state as much pretty explicitly in this post, and in other posts in this thread: http://www.reefcentral.com/forums/showpost.php?p=15968898&postcount=9

In other words, if one maintains low phosphate levels, the use of LR or aragonite sand does not present a long term problem. On the other hand, if one does not maintain low phosphate levels, having LR and aragonite sand can make reducing those levels rather difficult.

If I'm wrong on this, please correct me, but I did a couple quick searches and could not find anything that ran counter to my current understanding. Maybe I was a bit unclear in my original statement.

i am not sure how it can reach a equilibrium reaction within the levels we see in our systems. when the pH is above the dissolution state of calcium carbonate. i can see if the pH is below the dissolution state of aragonite, or if there is a compound that has a stronger pull of the phosphates, than the aragonite, but if the PO4 is bound, then it has to be unbound or pulled chemically from the aragonite. if this were true, then all we would have to do is run clean water constantly over the rock to clean it of phosphates, we know this doesn't work or we wouldn't need to "cook" LR or use an acid bath. something is not making sense here.

i think the equilibrium constant is much lower than what we can realize in our systems. this study is saying (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2810262/?tool=pubmed).

i know medical related, but this does mention the problem with low pH (http://www.medscape.org/viewarticle/506489_3).

Uptake of phosphate ions by calcium carbonate (http://www.terrapub.co.jp/journals/GJ/pdf/1201/12010029.PDF).this one is interesting in that stirring is needed to be the most effective leading me to think that it is not an equilibrium reaction. if it were an equilibrium reaction, than the stirring would not be necessary. maybe i am reading it wrong. of course it did not go into really low levels, and there was significant leveling off.

Adsorption of Phosphate on Calcium Carbonate (http://www.aoml.noaa.gov/flbay/millero1.html)

i have a feeling the problem we are having is that we do not know what the equilibrium constant for this reaction is. i would guess from the levels seen in nature and the various references, it looks like it is way lower than what we encounter in our systems.

quick info on the biological side (http://en.wikipedia.org/wiki/Phosphate_solubilizing_bacteria).

Hi G~ (Reefin' Dude),

Thanks for sharing your thoughts and expertise.

I am running my third reef tank, which is BB. In my previous two set ups and the early stages of my present tank, I used shallow aragonite sand bed (up to 1 " depth). Shortly after stocking with fish and corals, certain sections of my sand bed always solidified looking like a flat rock, which I was able to crumble with my hands, but sometimes I was not not able to do so. Was the solidification of the sand bed due to bacteria binding phosphates to calcium carbonate?

DH

not exactly, but it does have to do with all of them. from what i understand it is the bacterial activity in the substrate causing a drop in pH in the substrate. bacteria can create a lot of CO2. the drop in pH. this is the same process that sand bed supporters say allows for a substrate to provide Ca and alk to the system (another story). the lack of enough flow in the substrate creates a boundary layer somewhere in the substrate. when the dissolved aragonite hits a higher pH it binds back to itself. forming a clump.

so it is not the actual binding of the P to the aragonite, but all of the bacterial activity on the detritus in the substrate and a lack of good flow to help keep things moving enough.

G~

dkeller_nc
11/11/2013, 12:25 PM
This differs from my understanding based on what I've read from Randy (and other in hobby publications). His statements suggest that in our tanks, substantial release of phosphate from aragonite generally becomes an issue when phosphate concentration in the water remains elevated for a long time and then drops, or when a pH drop causes aragonite, and any phosphate precipitated onto it, to dissolve.

My understanding is that if one has consistently low phosphate levels, and steady pH, one is unlikely to experience much in the way of phosphate leaching back into the water. Is this incorrect?

Randy seems to state as much pretty explicitly in this post, and in other posts in this thread: http://www.reefcentral.com/forums/showpost.php?p=15968898&postcount=9

In other words, if one maintains low phosphate levels, the use of LR or aragonite sand does not present a long term problem. On the other hand, if one does not maintain low phosphate levels, having LR and aragonite sand can make reducing those levels rather difficult.

If I'm wrong on this, please correct me, but I did a couple quick searches and could not find anything that ran counter to my current understanding. Maybe I was a bit unclear in my original statement.

You aren't wrong. Calcium phosphate has a water solubility of about 20 parts per million expressed as the phosphate ion. The ratio of dissolved calcium phosphate to solid calcium phosphate depends on the water's concentration of free phosphate in the presence of calcium. So unless the water's concentration of phosphate is quite high (high by reefer's perspective, anyway), no appreciable amount binds to the substrate. However, if appreciable solid calcium phosphate is in the system and the concentration of dissolved phosphate in the water is very low, phosphate will leach back into the water from the solid sources.

This is a well established aspect of chemistry called Le Chatlier's principle governing the equilibrium state of chemical reactions. It's also called "the law of mass action".

Reefin' Dude
11/12/2013, 12:11 PM
found the full article for the link i posted before that is of most relevance to what we are talking about.

I. Project title: THE ROLE OF SUSPENDED CALCIUM CARBONATE IN THE PHOSPHORUS CYCLE IN FLORIDA BAY (http://www.aoml.noaa.gov/ocd/sferpm/millero/millero_final.html)

G~

jda
11/12/2013, 12:41 PM
My understanding is that if one has consistently low phosphate levels, and steady pH, one is unlikely to experience much in the way of phosphate leaching back into the water. Is this incorrect?


You are right, but not for the reasons that you might think.

What appears to be leeching of the phosphates is actually that the sand bed is incapable of doing it's job anymore by bonding and processing, so levels rise. The sand is "full." ...so not true leeching, but P levels will rise since they go unprocessed.

This surprises reefers who have had success for years of doing nothing to their sand. They are used to having no/little N and P, so they start with the assumption that it is not them - which makes sense since they have never/rarely "seen" it. At first incapable of realizing that they have always had it and not knowing that the sand has been taking care of the P, they assume that the sand much be "leeching" since it worked before. Some will get it when you explain the process, but some will not and blame the sand forever.

A properly maintained sand bed will continue to process and bond, which appears to "not be leeching."

In the end, it all gets back to proper routine maintenance, not a low presence of phosphate... but the low presence of phosphate is a product of the maintenance. ...so I guess that it is the same, but not really, but kinda, but kinda-not... IMO.

I am just a In Home Reefer Scientist, not a real Scientist and I did not even stay at a Holiday Inn Express last night, so... this is opinion is likely not worth the cost of the byes that it is stored in.

hart24601
11/14/2013, 04:45 PM
People tend to make it sound more difficult and complex than it is.

Most SPS require stable water chemistry, adequate water movement, adequate light, adequate nutrition, and reasonably clean water.

IME, many SPS corals are among the most hardy, least picky, and most bulletproof once established. My bird's nest is easily the fastest growing of my long term residents. Yesterday, I accidentally broke about 8 tips off of branches, and it had already grown back over and rounded off the broken edges by lights out tonight.

Most montis seem pretty indestructible. I have an M. mollis that was knocked onto a Galaxea when it was ~half dollar sized a few months ago. About 5 sq millimeters of tissue survived. Now, it is larger than it was when the incident occurred.

My Hydnophora is the only SPS I have that seems a bit finicky and slow growing. I recently moved it to a higher flow area, so we'll see if it's happier there.

Euphyllia are the corals that I can't keep happy for the life of me, and my Symphyllia is also pretty slow growing and touchy.

For whatever reason, my SPS always seem to be less offended by "minor" WQ issues, like application of aiptasia killing gunk near them, or a few hours with no flow, or a few days without 2 part, etc.

+1 While I have had trouble with some SPS most of them outgrow my other corals tenfold. My SPS have also been very tough, most my leathers died but not the SPS. Some of the nicest reef tanks you will ever see don't have anything fancy, just a few water changes. I have SPS of all types out growing my biocube for quite a long time now and that tank only gets serviced about once a month.

All these problems with calcium based rocks. Just use ceramic based live rock and substrate if desired.

dkeller_nc
11/17/2013, 09:42 AM
What appears to be leeching of the phosphates is actually that the sand bed is incapable of doing it's job anymore by bonding and processing, so levels rise. The sand is "full." ...so not true leeching, but P levels will rise since they go unprocessed.


This is actually not quite correct from the standpoint of the physical chemistry of the water and solid substrates. What is actually occurring is that at high phosphate concentrations in the water, calcium phosphate will precipitate on solid surfaces, including the aragonite in reef sand and live rock. However, this precipitation isn't irreversible, and the partition coefficient for calcium phosphate between the tank water and the aragonite substrate isn't all that high compared to something like ferric hydroxide (GFO). So when the tank water concentration is low, any calcium phosphate that's precipitated in the sand bed and on the rocks will re-dissolve.

So in this sense, it isn't possible to "fill up" a sand bed with phosphate unless the tank water concentrations remain quite high - well in excess of 1-2 ppm, which would be considered excessive by most SPS tank keepers.

This same principle applies to the binding of phosphate to ferric hydroxide - it's technically true that phosphate can leach back into seawater from the absorbed form on the GFO particles. But the partition coefficient is so incredibly high for ferrous phosphate that the water's phosphate concentration in equilibrium with ferric hydroxide is essentially zero.

Reefin' Dude
11/18/2013, 09:51 AM
where do you get the 1-2ppm from? in the study i linked to earlier clearly shows that phosphate absorption on calcium carbonate occurs at 2mM levels, until equilibrium is attained. this equates to about 0.187ppm PO4 in Salt water. how is that anywhere near 1-2ppm?

is it an equilibrium reaction or not. if it is, and it seems like it is from the study shown above, than why would it not be an equilibrium reaction all the way down to normal NSW levels of PO4, 0.005ppm at the minimum?

do you have the partition coefficient of calcium carbonate and ferric hydroxide?

G~

dkeller_nc
11/19/2013, 12:13 PM
If you mean the "Role of Suspended Calcium Carbonate in The Phosphorus Cycle of Florida Bay", the authors used:

5 mmol in 500 ml Phosphate for the adsorption kinetic studies, which equates to 950 ppm.

For the desorption kinetic studies, they saturated 2 grams of calcium carbonate with a 110 mmol phosphate solution, which equates to 10,450 ppm.

For the adsorption equilibrium studies, they used solutions ranging from 1 mM to 60mM, which equates to 95 ppm to 5,700 ppm.

In other words, they were doing their tests in concentrations of phosphate that vastly exceed what we would (hopefully) encounter in a reef tank, and the concentrations of ions in solution sensitively affect the partitioning (and % saturation) of these ions between precipitated and solution forms.

Reefin' Dude
11/20/2013, 02:57 PM
we know that calcium carbonate is a phosphate binder. that can not be disputed.

i think our disagreement is in how much P it can bind and what "equilibrium" means.

in this study:

Calcium Carbonate Phosphate Binding Ion Exchange Filtration and Accelerated Denitrification Improve Public Health Standards and Combat Eutrophication in Aquatic Ecosystems (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2810262/)

"Sump water and water throughout the marsh, especially in the northwest corner, have average phosphate concentration of 2.34 ppm (7.51 × 10−6 mol/L)."

"The amount of calcium carbonate needed to decrease phosphate, as determined from the reaction calculation, by a certain amount in a certain amount of water was calculated to be 4.78 × 10−4 moles per liter per ppm phosphate, as follows:

(CaCO3)=Kcp([PO43−])(V),
(4)
where Kcp = 4:78 × 10−4 moles per liter per ppm phosphate For CaCO3 in milligrams, Kcp = 48:7 The data from the calcium carbonate reaction mechanism analysis lead directly to the calcium carbonate lacing procedure. A phosphate level of 0.75 ppm was desired for testing purposes, and the results were very accurate. The average phosphate levels after the addition of calcium carbonate came to a statistically significant (p < 0.001) 0.74 ppm (Figure 5), which is well within the statistically significant range (p < 0.01)."

is not that volume of calcium carbonate they used far less than the amount of calcium carbonate we have in our systems with just regular live rock, not to mention any substrate that may be used? as long as the calcium carbonate media in our systems has less P than the water column, and greater than the formula listed above there will be P binding going on correct?

the data for the other water volumes is even better for the use of calcium carbonate as a phosphate binder.

G~

jda
11/20/2013, 03:04 PM
In the "JDA's Reefs Since 1992 Study" calcium carbonate can bind enough phosphates so that since a Salifert Test kit was introduced for Phosphate, there have never been any detectable results with no fuge, GFO (like they had it back then) or carbon dosing. I am pretty sure that it can keep an equilibrium of near zero - obviously I have enough to keep the SPS growing and even some hair or other algae if my CUC is not on their game. Is this science, or what?

I am not sure which study is saying what, but in a typical tank, I think that aragonite does just fine keeping the phosphates more than manageable.

dkeller_nc
11/21/2013, 10:53 AM
as long as the calcium carbonate media in our systems has less P than the water column, and greater than the formula listed above there will be P binding going on correct?
G~

Yes, and the calcium carbonate in the system will desorb phosphate just as rapidly when the water column is low in phosphate.

So in that sense one cannot irreversibly "fill up" the sand bed or LR in an aquarium with phosphate. You can keep a very high phosphate input to the tank with no other substantive means of removal and both "saturate" the substrate and water column with phosphate. But as soon as you lower the water concentration of phosphate by protein skimming, water changes, and/or use of GFO and other phosphate absorbers, the sand bed will give up that bound phosphate.

That will, of course, affect how fast the phosphate concentrations in the water column will come down upon the implementation of phosphate absorption/dilution strategies, but the ultimate end point is the same.

jda
11/21/2013, 11:12 AM
Is this something that you are supposing based on literature and studies, or based on your own experiences? I am not doubting or anything, just looking to qualify. I have not found the same thing with my own experiences, so I am looking to learn and perhaps restudy.

I have not have the same experiences firsthand. I can have tank water levels of P that are undetectable (on salifert), but if I remove some of the sand from places in my tank and melt it in some CO2 water for a few days, the phosphates test fairly high at around .25 to .30 in aggregate. Anecdotally, the more "maintained" places in the sand are around .10 and the less "maintained" around .50. I am sure that if I dissolved more, then levels would further elevate. I have personally found that the sand bed does not give up the bound phosphate when the water levels are low.

I suppose that my hypothesis is wrong and the sand could be giving up P in low tank level conditions. However, if it is, then what is happening to it? I don't use GFO, dose carbon to consume it?

Allmost
11/21/2013, 11:17 AM
anything used too much, will cause STN / RTN..

even if you fart by your skimmer too much, your corals will STN !

but farts are not a big STN factor.

jda
11/21/2013, 11:18 AM
You might be onto something there... methane reactor to feed into the skimmer pump for better organic bonding.

Reefin' Dude
11/21/2013, 03:16 PM
Yes, and the calcium carbonate in the system will desorb phosphate just as rapidly when the water column is low in phosphate.

So in that sense one cannot irreversibly "fill up" the sand bed or LR in an aquarium with phosphate. You can keep a very high phosphate input to the tank with no other substantive means of removal and both "saturate" the substrate and water column with phosphate. But as soon as you lower the water concentration of phosphate by protein skimming, water changes, and/or use of GFO and other phosphate absorbers, the sand bed will give up that bound phosphate.

That will, of course, affect how fast the phosphate concentrations in the water column will come down upon the implementation of phosphate absorption/dilution strategies, but the ultimate end point is the same.

if phosphates behave equilibrium like you say, then yes you are correct for the calcium carbonate in direct contact with the open water column. unfortunately (or fortunately depending on which side of the poo as a pet camp you are on) the substrate itself is an ever increasing permeable barrier to the equalization. this along with the fact that as detritus is worked down into the substrate the amount of P in direct contact with the calcium carbonate goes up, which in turn increases the amount of P that can bind to the calcium carbonate until all binding sites are full. luckily for those that use a substrate all of that bacterial activity and worms help in the slow migration of this slow increasing level of P.

of course we know that this is occurring because of the life that is in the substrate. if the P was not there to feed the organisms, than they would not be there. how much poo does one want to keep as a pet.

if one were to mix the substrate layers and the more P laden calcium carbonate were now up on top, than there would be a release of P from the calcium carbonate into the open water column if P reaches equilibrium with the calcium carbonate and the open water column.

substrates acts as P sinks.

G~

dkeller_nc
11/22/2013, 07:32 AM
substrates acts as P sinks.

G~

Yes, in the sense that they can act as a dynamic reservoir for phosphate in a high PO4 environment. But the problem is - so does the live rock, or any other calcium carbonate in the system. In this sense, it is highly illogical to declare that substrates are ultimately damaging to the maintenance of a reef tank, but live rock isn't (neither of them are harmful).

dkeller_nc
11/22/2013, 07:40 AM
Is this something that you are supposing based on literature and studies, or based on your own experiences?

An understanding of physical chemistry, actually. But also my own experiences and literature.

From the standpoint of your observations, there may well be a perfectly logical alternative explanation. When you dissolve a solid substrate in an acid and test the ionic composition of the dissolved liquid, you get a total picture of the average composition of the solid material.

But in general, that doesn't mean it acquired that composition in one's reef tank, in fact it's highly unlikely that it did so. What is considerably more probable based on the mass balance is that the outcome of such testing gives insight into the composition of the material when it went into the reef tank.

Reefin' Dude
11/22/2013, 07:42 AM
Yes, in the sense that they can act as a dynamic reservoir for phosphate in a high PO4 environment. But the problem is - so does the live rock, or any other calcium carbonate in the system. In this sense, it is highly illogical to declare that substrates are ultimately damaging to the maintenance of a reef tank, but live rock isn't (neither of them are harmful).

LR can be in the open water with flow all around it. it is able to self clean, which a substrate is not able to do.

a substrate is more likely to be harmful, while LR could not be. this is especially true if one treats the substrate in the manner most recommended. do not touch it. if LR is not exposed to enough flow all around it, then yes, you are right it can become as much of a P sink as a substrate. a substrate is always going to be a P sink. the only way to keep it from being so is if it is siphoned cleaned or replaced on a regular basis to remove all of the detritus from it. as long as there is detritus in the substrate, than the calcium carbonate around the detritus is going to have an elevated P level than the calcium carbonate not in direct contact with detritus or other waste products.

G~

Reefin' Dude
11/22/2013, 07:46 AM
An understanding of physical chemistry, actually. But also my own experiences and literature.

From the standpoint of your observations, there may well be a perfectly logical alternative explanation. When you dissolve a solid substrate in an acid and test the ionic composition of the dissolved liquid, you get a total picture of the average composition of the solid material.

But in general, that doesn't mean it acquired that composition in one's reef tank, in fact it's highly unlikely that it did so. What is considerably more probable based on the mass balance is that the outcome of such testing gives insight into the composition of the material when it went into the reef tank.

could it be the fact that the calcium carbonate in the substrate has been exposed to detritus all around it? detritus has a high P content. if calcium carbonate is an equilibrium reaction, and a substrate is a semi-permeable barrier, than as one goes deeper in the substrate, the more P there is going to be. if there is more P, than there is more P on the calcium carbonate to reach equilibrium, correct? not sure how this does not make sense.

G~

dkeller_nc
11/22/2013, 08:06 AM
this along with the fact that as detritus is worked down into the substrate the amount of P in direct contact with the calcium carbonate goes up, which in turn increases the amount of P that can bind to the calcium carbonate until all binding sites are full.

how much poo does one want to keep as a pet.

if one were to mix the substrate layers and the more P laden calcium carbonate were now up on top, than there would be a release of P from the calcium carbonate into the open water column if P reaches equilibrium with the calcium carbonate and the open water column.

A couple of final thoughts, and then I'm going to bow out of this discussion since the argumentation has been reasonably well discussed.

First, it is generally incorrect to think in terms of "direct contact" in the context of liquid-solid system. There is always a significant liquid interface between particles in any packed bed, whether it's a sand bed in an aquarium or media in a reactor. Reactions and adsorption/desorption proceed by physical mechanisms of diffusion through this boundary layer of liquid.

Moreover, in aqueous systems this diffusion between the bulk liquid and the particles is extremely quick - on the order of 1 or 2 seconds. It is true that one can establish a gradient between the bulk liquid and some point down into the packed bed, but this is a dynamic gradient caused by continuous physical and biochemical processes that are continually consuming or giving up chemical compounds. That's why it's possible to develop anoxic conditions within a sand bed.

But, no matter one's preferences, it is fundamentally incorrect to think of a sand bed (or any packed bed or substrate such as LR) as a reservoir of binding sites for phosphate that can be irreversibly filled up. There is always an exchange between the bulk liquid and solid material, and if one or the other is "deficient" in phosphate, then phosphate will transport to that phase. This is fundamental to chemistry and physics, and is sometimes referred to colloquially as "nature abhors a vacuum".

If this were not true, then the sand, live rock, and any other solid calcium carbonate in the ocean would be completely and irrevocably saturated with calcium phosphate. And it would be utterly impossible to leach this phosphate back out of the sand or rock as is commonly and repeatably done by hobbyists.

Reefin' Dude
11/22/2013, 10:55 AM
A couple of final thoughts, and then I'm going to bow out of this discussion since the argumentation has been reasonably well discussed.

understood, but it seems like there is still a good amount of discussion left.

First, it is generally incorrect to think in terms of "direct contact" in the context of liquid-solid system. There is always a significant liquid interface between particles in any packed bed, whether it's a sand bed in an aquarium or media in a reactor. Reactions and adsorption/desorption proceed by physical mechanisms of diffusion through this boundary layer of liquid.

Moreover, in aqueous systems this diffusion between the bulk liquid and the particles is extremely quick - on the order of 1 or 2 seconds. It is true that one can establish a gradient between the bulk liquid and some point down into the packed bed, but this is a dynamic gradient caused by continuous physical and biochemical processes that are continually consuming or giving up chemical compounds. That's why it's possible to develop anoxic conditions within a sand bed.

wouldn't the existence of an anoxic condition indicate that there is not an extremely quick diffusion between all of the layers? if the anoxic layer is just a few cm below the surface, than why wouldn't a solid like P also be increasing if a gas such as O2 could not diffuse quick enough between the water surface interface to maintain constant levels within seconds? something is not making sense? either there can be adequate diffusion to maintain equilibrium, or there can not be. wouldn't a gas have a higher affinity to maintain equilibrium, than a solid?

But, no matter one's preferences, it is fundamentally incorrect to think of a sand bed (or any packed bed or substrate such as LR) as a reservoir of binding sites for phosphate that can be irreversibly filled up. There is always an exchange between the bulk liquid and solid material, and if one or the other is "deficient" in phosphate, then phosphate will transport to that phase. This is fundamental to chemistry and physics, and is sometimes referred to colloquially as "nature abhors a vacuum".

you are correct if there is sufficient movement of media to allow for the equalization of P between the solid calcium carbonate and the liquid media. the problem is that we are not only dealing with P in the water, we are dealing with the P from detritus. it is this P that is causing the increase in P of the calcium carbonate media that is around the detritus. if detritus did not accumulate in our systems, than we would not have to worry about our systems increasing in P over time. if one were to remove all detritus from a substrate in a timely manner, than there will not be an increase in P on the calcium carbonate in the substrate in contact with the detritus. there is a constant give and take between bacteria and the calcium carbonate for available inorganic P.

Phosphorous accumulation in marine sediments and the oceanic phosphorous cycle. (http://web.mit.edu/qhorn/Public/Reef%20Aquariums/Phosphorus%20articles/Delaney%20Global%20Bio%20Cyc%2012%204%201998.pdf)

If this were not true, then the sand, live rock, and any other solid calcium carbonate in the ocean would be completely and irrevocably saturated with calcium phosphate. And it would be utterly impossible to leach this phosphate back out of the sand or rock as is commonly and repeatably done by hobbyists.

luckily for us bacteria like the P more than the calcium carbonate. they use the P for their own biological functions. all organisms need P for an energy source. only bacteria are able to access P directly from a solid media. even true plants have to wait until P is in an aqueous solution before they can utilize inorganic P.

Phosphate solubilizing bacteria (http://en.wikipedia.org/wiki/Phosphate_solubilizing_bacteria)

Phosphorus Uptake by Plants: From Soil to Cell (http://www.plantphysiol.org/content/116/2/447.full)

all of the examples of the phosphate cycle on Earth show that substrates are a P sink, and that erosion is main supplier of P back into the ecosystem.

http://www.thereeftank.com/gallery/files/2/0/5/0/phosphoruscycle.gif

http://images.tutorvista.com/content/ecosystem/phosphorus-cycle.jpeg

G~

dkeller_nc
11/25/2013, 08:48 AM
understood, but it seems like there is still a good amount of discussion left.

OK - a few more posts, but this discussion is a bit off-topic for this thread, so if you would like a broader discussion, I'd suggest posting a thread under the "Reef Chemistry" section with this subject in the thread title.



wouldn't the existence of an anoxic condition indicate that there is not an extremely quick diffusion between all of the layers? if the anoxic layer is just a few cm below the surface, than why wouldn't a solid like P also be increasing if a gas such as O2 could not diffuse quick enough between the water surface interface to maintain constant levels within seconds? something is not making sense? either there can be adequate diffusion to maintain equilibrium, or there can not be. wouldn't a gas have a higher affinity to maintain equilibrium, than a solid?

Not exactly. There are two things at work - one is distribution of a chemical species in a liquid (in this case, the liquid around the substrate in the sand bed) by diffusion and/or convective flow. The other aspect that determines what the concentration of a particular species is at any particular depth is rate of consumption and the concentration of the species in the bulk liquid. Diffusion is still remarkably quick between the substrate particles and the bulk liquid in the sandbed in this sort of system, but a gradient still exists between the top surface and the interior of the sandbed because the oxygen is being consumed by microorganisms.

The diffusion rate of chemical species in a liquid varies, but not appreciably for the purposes of this discussion. You are correct that diffusion in a gas phase is much faster than in a liquid phase, but once the gas dissolves into the liquid phase, its rate of diffusion is similar to other dissolved species.



you are correct if there is sufficient movement of media to allow for the equalization of P between the solid calcium carbonate and the liquid media. the problem is that we are not only dealing with P in the water, we are dealing with the P from detritus. it is this P that is causing the increase in P of the calcium carbonate media that is around the detritus. if detritus did not accumulate in our systems, than we would not have to worry about our systems increasing in P over time. if one were to remove all detritus from a substrate in a timely manner, than there will not be an increase in P on the calcium carbonate in the substrate in contact with the detritus. there is a constant give and take between bacteria and the calcium carbonate for available inorganic P.

I'm not saying that phosphate cannot precipitate or bind to aragonite or calcite in our systems - it clearly can. But it's not irreversible binding, and re-dissolution of the bound phosphate will occur quite quickly if the water's concentration of phosphate is dropped to low values. This will occur regardless of the source of phosphate - be it detritus, abiotically precipitated calcium phosphate, or the surface of dolomitic limestone. [/quote]



luckily for us bacteria like the P more than the calcium carbonate. they use the P for their own biological functions. all organisms need P for an energy source. only bacteria are able to access P directly from a solid media. even true plants have to wait until P is in an aqueous solution before they can utilize inorganic P.


There is no question that there are some soil bacteria that are capable of re-dissolution of solid phosphate, but I'd be cautious about extrapolating that to conclude that these kinds of bacteria are active in the ocean environment and in our tanks. Perhaps this will turn out to be the case, but perhaps not. You will notice, for example, that the phosphorus cycle diagrams that you posted don't include a large recycle component from ocean sediment back into the water column by bacteria.

Reefin' Dude
11/25/2013, 10:01 AM
You will notice, for example, that the phosphorus cycle diagrams that you posted don't include a large recycle component from ocean sediment back into the water column by bacteria.

nor from simple equalization. this is why i have a hard time believing that it equalizes as well as has been suggested. if it did, than we would see equal arrows going into and out of a substrate showing equalization. all we see are arrows going into the substrate.

G~

dkeller_nc
11/27/2013, 07:03 AM
One explanation for that may be the form of phosphate that is being depicted. There are lots of compounds that contain phosphate, many of them as part of an organic molecule. In the ocean, a lot of organic material precipitates as "marine snow" before it has an opportunity to be broken down by bacteria or eaten by other organisms.

My speculation would be that since this marine snow is continuous, and the waters of the deep ocean are very cold and have much slower bacterial decomposition than surface/shallow waters, the phosphate in this marine snow is getting continuously buried and not recycled back into the water column. After a few eons, this material has been incorporated into rock, which eventually makes it onto the continents. This continental rock is weathered by action of rain/snow, so the phosphate is eventually returned to the ocean by this mechanism.

It'd be kind of hard to duplicate that process in a reef tank. ;)

Reefin' Dude
11/27/2013, 09:53 AM
the charts are showing a combination of both inorganic and organic, but primarily inorganic P directions. unfortunately for us we can only test for inorganic P. this is why we need to use biomarkers to tell us what the total P of a system actually is. the more biomass in the system, the more total P. biomass is organically bound P. the unfortunate part is that in order to have organically bound P in a given biomass there must be an enough food to support the biomass. if this is the food we add great, but if the biomass is feeding on waste products from other organisms, than this will also indicate a larger sink of P in the system. :(

actually it is quite easy to replicate in a reef tank. just siphon out the substrate on a regular basis, or replace the substrate completely as routine maintenance. we become plate tectonics.

G~

mesocosm
11/28/2013, 07:51 AM
Greetings All

Is there any evidence, that biopellets can cause STN/RTN? ... There are many anecdotal reports of high alkalinity + biopellets being correlated to STN, but no "hard" evidence of a causal relationship.


I recently began running biopellets on my 210 that all inhabitants moved from my 150. Many of the acro colonies have grown from small frags to 4-8" colonies. I'm experiencing 50-75% of my acro's experiencing slow tissue necrosis. The transfer of SPS specimens from systems in which they have long thrived to different systems often proves difficult.


Another odd scenario is that it tends to be centralized/affected on the right side of the tank. This might indicate that the difficulties are arising from light and/or flow variables, as opposed to biopellets. If the source of the problem was biopellets one would expect that there would be no locational variable.


JMO ... HTH
:thumbsup:

dkeller_nc
11/30/2013, 08:10 AM
actually it is quite easy to replicate in a reef tank. just siphon out the substrate on a regular basis, or replace the substrate completely as routine maintenance. we become plate tectonics.

Actually, I was referring to duplicating subduction and the resultant earthquakes and volcanoes. Sounds much more interesting than phosphate management. ;)

lanshark
11/30/2013, 08:57 PM
Reef'in Dude, All this pontificating ........ Where is "the beef" ? As you have such a ABSOLUTE understanding of the topics being discussed, it is a shame you don't show us the real life application of your "book smarts"? Those that can, do... Those that can't, ?

Reefin' Dude
12/05/2013, 10:57 AM
Actually, I was referring to duplicating subduction and the resultant earthquakes and volcanoes. Sounds much more interesting than phosphate management. ;)

i know, though it would be fun to have that going on. :D

Reef'in Dude, All this pontificating ........ Where is "the beef" ? As you have such a ABSOLUTE understanding of the topics being discussed, it is a shame you don't show us the real life application of your "book smarts"? Those that can, do... Those that can't, ?

sorry, you are correct. i have posted my build thread a few times. here it is again (http://www.thereeftank.com/forums/f6/the-rebuild-begins-63881.html?highlight=rebuild+begins). again, i have not had a chance to start up another tank after the divorce and getting the new house the way it needs to be before a largish (250g+) system can be added.

for another example from the person that got me started on doing all of the research on nutrients is Bomber.

spanky's starboard reef circa 11/2004 (http://www.thereeftank.com/forums/f6/spankys-starboard-reef-circa-11-2004-a-42513.html)

Pictures of Bomber's barebottom SPS tank and related equipment (http://www.reefcentral.com/forums/showthread.php?t=292233&highlight=jerel+reef+tank)

if you haven't come across any Bomber/Spanky threads then it is worth anybody's time to find them. there are unfortunately not a lot of them left here on RC since the RC server crash back in 2005.

G~

simonh
12/05/2013, 11:25 AM
I remember those threads well!

How's Bomber's tank these days?

Is he still active on any forums?

Reefin' Dude
12/05/2013, 11:32 AM
i have not talked with him in a year. he is not on any forums anymore. after the big shakedown in the aquarium hobby industry he left the forums completely. that was in 2006. he took the tank down a few years later and stopped breeding clowns also a few years after that.

i had a ton of bookmarked threads from here, but the RC server crash seemed to have taken most of them out. if you have any saved, i would like to know if they work for you. luckily there are a lot of his threads elsewhere that i have links for.

G~

GroktheCube
12/05/2013, 11:53 AM
Reef'in Dude, All this pontificating ........ Where is "the beef" ? As you have such a ABSOLUTE understanding of the topics being discussed, it is a shame you don't show us the real life application of your "book smarts"? Those that can, do... Those that can't, ?

There's no need for anyone to get so worked up. There's plenty of room for debate without personal insults!

Personally, if it weren't for the fact that I wanted sand dwelling critters like conches, I probably would have used a faux-sand bed (sand + epoxy) for my tank, as I think it would have made maintenance, nutrient management, and dead spot prevention easier. I'd still like to try a tank like that some day.

That said, I don't think having a sand bed in my tank will cause substantial problems. I keep dissolved nutrient levels low. Every month or so I heavily baste the rocks and stir the sand to remove any accumulated detritus, and run filter socks for a day or two to catch it. If a spot looks dirty, I'll vacuum it out and replace it with clean sand.

A lot of it comes down to what an individual wants out of their tank. However, if you don't care about critters that need sand to be happy, and only care about sand for aesthetics, I think that a faux sand bottom most likely makes for the overall easier experience from a maintenance perspective.

Reefin' Dude
12/05/2013, 12:08 PM
+1

nobody is telling anybody they can not have sand in their tank. people are just pointing out what the sand is actually doing. it is up to the aquarist to decide where on the maintenance/cost curve they want to be on for the emulated environment they wish to keep in their systems. if you want to keep a softie tank or a tank that has an organisms that requires sand, then sand is absolutely the recommended way to go. if one wants to keep an true oligotrophic system, then keeping sand in the tank is going to require more maintenance/cost, than going with a BB system.

all that is being said is know the organisms that one wants to keep, then adapt the tank to the parameters needed to keep that organism. just because the organism cam from a warm salt water environment does not mean that it came from the same warm salt water environment of another organism. corals have adapted to very tight nutrient level niches. we must look at the nutrient levels that an organism needs as well as its temp, and S.G. levels and adapt the system to match.

a substrate does a lot, but it is not a magic worm hole to another dimension for nutrients. know what it does good and what it does bad, and use that knowledge to decide how you want to do maintenance.

G~

Osteoclast
12/05/2013, 06:01 PM
As an aside: Boomer may be gone from RC but he is posting/answering queries on Manhattan Reefs in the chemistry section. He continues to provide good information to the readers and current topics are discussed from a leader (giant) in the hobby.

DiscusHeckel
12/05/2013, 06:23 PM
As an aside: Boomer may be gone from RC but he is posting/answering queries on Manhattan Reefs in the chemistry section. He continues to provide good information to the readers and current topics are discussed from a leader (giant) in the hobby.

He is also the moderator in the chemistry forum on Reef Frontiers. :)

simonh
12/06/2013, 01:59 AM
Boomer and Bomber/Spanky are two different people

Osteoclast
12/06/2013, 03:11 AM
Simon,
Thanks I stand corrected. Bomber is/was a reef giant similar to Boomer with an expansive knowledge of the hobby, the science, and the methodology. His arguements were well constructed here at RC and on other forums RT among others. Any novice in reef keeping would do well to study his comments, posts, and writings. (Perhaps I was overwhelmed by Boomer's unforgettable avatar!)

CW from the OC
12/29/2013, 11:02 PM
Anytime you go to a ultra low nutrient system,you run the risk of starving your SPS. That is why methods like Zeo are so careful once the nutrients get to low. You can't just pop in a ton of pellets and assume your SPS will be fine. Once you get to low nutrients, you need to kick up your feeding, a lot. Feed until your SPS grow, and/or you start getting nuisance algae. There is no auto pilot on an SPS system, at least,from what I've seen.

chercm
12/30/2013, 06:05 PM
Anytime you go to a ultra low nutrient system,you run the risk of starving your SPS. That is why methods like Zeo are so careful once the nutrients get to low. You can't just pop in a ton of pellets and assume your SPS will be fine. Once you get to low nutrients, you need to kick up your feeding, a lot. Feed until your SPS grow, and/or you start getting nuisance algae. There is no auto pilot on an SPS system, at least,from what I've seen.

can i confirm i kept getting hair algae is it i did not feed enough ?

SomeDude12
01/03/2014, 07:45 AM
anything used too much, will cause STN / RTN..

even if you fart by your skimmer too much, your corals will STN !

but farts are not a big STN factor.

Haha!