Biopellets causing Acropora to STN/RTN?

[Reefin' Dude]

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]

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]

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]

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]

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. the conversion of P. ATP, ADP, and the 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. so well that it is used in kidney dialysis. if this study isn't telling, then i do not know what is.

"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.

G~

 

[simonh]

calcium carbonate does a very good job at binding phosphates. so well that it is used in kidney dialysis. if this study isn't telling, then i do not know what is.

"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]

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

it is even listed as a phosphate binder when you look up phosphate binders 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]

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

it is even listed as a phosphate binder when you look up phosphate binders 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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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.

i know medical related, but this does mention the problem with low pH.

Uptake of phosphate ions by calcium carbonate.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

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.

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]

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".