RDSB for ~400g water. Help please.

[Jeff000]

My 330g tank is almost ready to fill. It has a 220g sump. After rocks and water level in the sump, I figure about 400g of water.

I want to do a remote deep sand bed.
I can do up to 36 long by 12 wide, by however deep I need.
Is that enough for my water volume?
How deep should it be?
Is there a GPH flow that should be going through it?
Sugar fine sand?

Tank will be dark, and I can put what ever sized bulk heads into it.

Thanks in advance.

 

[Humu Humu]

Jeff,

I run a DSB in my Display Tank. I've read that 6" is the minimum for a deep sand bed. Even 8 if you can do it. Much more isn't really supposed to do much. Some people use a 5 gallon bucket filled almost all the way to the top.

When I set up my next tank, I'm going to use a RDSB, as putting it in the display is such a mess. As far as flow goes, my suggestion is to run a brisk flow over the bed, enough to keep suspended particles from settling out, but not too fast to disturb the sand particles. Do a search here for RDSB and you will find more information.

Another idea I have, is instead of putting the sand in my sump, put it into a removable plastic tub, in line with the sump and return. That way, when you need to replace the sand bed, you disconnect the tub and pull it out, rather than scooping all the sand from your sump.

good luck.

Dave

 

[Reefin' Dude]

as slow a flow as possible. you want all of the detritus to settle in the RDSB. that way it can be incorporated into the calcium carbonate matrix. in other words use the calcium carbonate for what it does very well absorb phosphates. then when you start to see algae growing in the RDSB it is time to replace the RDSB with a new one.

keeping a high enough flow not to collect detritus in the RDSB just means the phosphate laden detritus will settle somewhere else, probably in a less convenient place to get to and remove. waste has to be removed or the system is becoming eutrophic. why make it harder by not collecting it in a single area?

as has been discussed in another thread. i would turn this RDSB into a conical settling tank, or at the very least a completely empty tank to facilitate detrital removal.

G~

 

[Steve175]

Ony my 1500G system, I have a 150G water storage tank which I drilled a bulkhead on the side near the top. I have water pumping (manifold off large return pump) from the sump into the tank which flows back into the sump. The tank is full of ~ 40" of aragonite. I have struggled to keep my nitrates high enough (which my fish love)

 

[Jeff000]

as slow a flow as possible. you want all of the detritus to settle in the RDSB. that way it can be incorporated into the calcium carbonate matrix. in other words use the calcium carbonate for what it does very well absorb phosphates. then when you start to see algae growing in the RDSB it is time to replace the RDSB with a new one.

keeping a high enough flow not to collect detritus in the RDSB just means the phosphate laden detritus will settle somewhere else, probably in a less convenient place to get to and remove. waste has to be removed or the system is becoming eutrophic. why make it harder by not collecting it in a single area?

as has been discussed in another thread. i would turn this RDSB into a conical settling tank, or at the very least a completely empty tank to facilitate detrital removal.

G~

This is the first time I have ever read that you want detritus to settle on a RDSB. And I read all 40+ pages of the RDSB thread.

The main part of my sump (a 60x30) area will house equipment and some rocks to catch detritus for an easy one place to vacuum location.

Jeff,

I run a DSB in my Display Tank. I've read that 6" is the minimum for a deep sand bed. Even 8 if you can do it. Much more isn't really supposed to do much. Some people use a 5 gallon bucket filled almost all the way to the top.

When I set up my next tank, I'm going to use a RDSB, as putting it in the display is such a mess. As far as flow goes, my suggestion is to run a brisk flow over the bed, enough to keep suspended particles from settling out, but not too fast to disturb the sand particles. Do a search here for RDSB and you will find more information.

Another idea I have, is instead of putting the sand in my sump, put it into a removable plastic tub, in line with the sump and return. That way, when you need to replace the sand bed, you disconnect the tub and pull it out, rather than scooping all the sand from your sump.

good luck.

Dave

Thanks, I am going to have a remote tank just for the DSB. I think going to use a 29g tall, and put 10" in for good measure, but worried a bit about it over flowing.

Ony my 1500G system, I have a 150G water storage tank which I drilled a bulkhead on the side near the top. I have water pumping (manifold off large return pump) from the sump into the tank which flows back into the sump. The tank is full of ~ 40" of aragonite. I have struggled to keep my nitrates high enough (which my fish love)

Why would you want nitrates? and why would the fish love it?

 

[Reefin' Dude]

This is the first time I have ever read that you want detritus to settle on a RDSB. And I read all 40+ pages of the RDSB thread.

how does a DSB work? did they go through how a RDSB work in that thread? does it make any sense?

if what it "processes" is inorganic, then how do the inorganic nutrients get into the RDSB? how can a DSB/RDSB "process" nitrates when they are in the water column, and nitrates need to be "processed" by bacteria in a low oxygen environment?

DSB's work by the slow migration of detritus through them. the give and take between the bacteria and the calcium carbonate matrix slowly work the wastes down through the depth of the DSB. in the "process" temporarily locking up the phosphates and nitrates up. this is why it is unadvised to disturb a DSB/RDSB. you will release all of the nutrients that have been temporarily locked up in the substrate. if DSB work they they should, then why would we have to worry about disturbing a DSB/RDSB. it should always be as clean as the day you put it in all the way through its entire depth. unfortunately that is not how it really works. as you go deeper into an established substrate the higher the phosphate and nitrate levels will be from the accumulated waste products.

so, why would you not want detritus to settle on a DSB/RDSB, if this is how they work? why would you even want one if you have an area that accumulates all of the detritus in a single area for easy removal. that way you are skipping the entire "process" of what is going on in the DSB/RDSB. why have more steps than necessary. the phosphates and the nitrates that we test for are inorganic. the only way to get inorganic phosphates in our system is through rotting waste products. remove them, then you remove the source for inorganic nutrients.

G~

 

[Jeff000]

how does a DSB work? did they go through how a RDSB work in that thread? does it make any sense?

if what it "processes" is inorganic, then how do the inorganic nutrients get into the RDSB? how can a DSB/RDSB "process" nitrates when they are in the water column, and nitrates need to be "processed" by bacteria in a low oxygen environment?

DSB's work by the slow migration of detritus through them. the give and take between the bacteria and the calcium carbonate matrix slowly work the wastes down through the depth of the DSB. in the "process" temporarily locking up the phosphates and nitrates up. this is why it is unadvised to disturb a DSB/RDSB. you will release all of the nutrients that have been temporarily locked up in the substrate. if DSB work they they should, then why would we have to worry about disturbing a DSB/RDSB. it should always be as clean as the day you put it in all the way through its entire depth. unfortunately that is not how it really works. as you go deeper into an established substrate the higher the phosphate and nitrate levels will be from the accumulated waste products.

so, why would you not want detritus to settle on a DSB/RDSB, if this is how they work? why would you even want one if you have an area that accumulates all of the detritus in a single area for easy removal. that way you are skipping the entire "process" of what is going on in the DSB/RDSB. why have more steps than necessary. the phosphates and the nitrates that we test for are inorganic. the only way to get inorganic phosphates in our system is through rotting waste products. remove them, then you remove the source for inorganic nutrients.

G~

Might be a good read for you. It is my understanding this is NOT how a remote DSB works. The RDSB is for the nitrates in the water column, not to process detritus.

http://reefcentral.com/forums/showthread.php?t=595109&highlight=rdsb&page=40

http://reefcentral.com/forums/showthread.php?threadid=896352

 

[Reefin' Dude]

i will read them again, but i have a pretty good understanding on how inorganic nutrients get into the water column. which is why what is being said in the threads is not exactly what is going on. it IS ALL about the processing of wastes. the point i was making above, was. how does the nitrates get into the RDSB for "processing"? if nitrates are only able to be "processed" in a low oxygen environment. then how does the nitrates get to these areas? why would they not just stay in the water column? what mechanism is "pulling" the nitrates from the water column into the areas that are low in oxygen? they just want to because we want them to?

G~

 

[Meanmike]

No expert here but I have never heard that you want detritus to settle in a rdsb either. And no offense but I would take the word of Anthony Calfo over you.

 

[Reefin' Dude]

do a little independent research on your own and make up your own mind. read about phosphate mining. read about nutrient import in plant/algae. i could not care less if you take my word or not. who makes sense? i have been in this hobby 20+ years. have read through volumes written by experts that have then been proven to be wrong. the only thing i believe about a system is that in order for any system to be successful indefinitely the exports must equal imports. other than that, then the law of conservation of mass is not occurring and the system is becoming more eutrophic.

just use your brains. how does a RDSB work? why does it need to be unlit? what if it were lit? i bet it would grow a ton of algae because of all of the inorganic nutrients that would be building up in the area. then why not have it lit and use the algae as a nutrient export when you remove the algae? am i the only one that things all of this advice is just contradictory? shouldn't it all just make sense?

this hobby can make a lot more sense if you believe in the law of conservation of mass. if you find contradictory information ask how are nutrients not building up? then make up your own mind.

G~

 

[Jeff000]

i will read them again, but i have a pretty good understanding on how inorganic nutrients get into the water column. which is why what is being said in the threads is not exactly what is going on. it IS ALL about the processing of wastes. the point i was making above, was. how does the nitrates get into the RDSB for "processing"? if nitrates are only able to be "processed" in a low oxygen environment. then how does the nitrates get to these areas? why would they not just stay in the water column? what mechanism is "pulling" the nitrates from the water column into the areas that are low in oxygen? they just want to because we want them to?

G~

Nitrates get into the sand by diffusion. Put some red dye in the bottom of barrel full of sand then fill it with water, the water will all be dyed in fairly short order.

You are talking more about a traditional DSB, like you would have in your tank. The remote DSB is more for what's already in the water column.

do a little independent research on your own and make up your own mind. read about phosphate mining. read about nutrient import in plant/algae. i could not care less if you take my word or not. who makes sense? i have been in this hobby 20+ years. have read through volumes written by experts that have then been proven to be wrong. the only thing i believe about a system is that in order for any system to be successful indefinitely the exports must equal imports. other than that, then the law of conservation of mass is not occurring and the system is becoming more eutrophic.

just use your brains. how does a RDSB work? why does it need to be unlit? what if it were lit? i bet it would grow a ton of algae because of all of the inorganic nutrients that would be building up in the area. then why not have it lit and use the algae as a nutrient export when you remove the algae? am i the only one that things all of this advice is just contradictory? shouldn't it all just make sense?

this hobby can make a lot more sense if you believe in the law of conservation of mass. if you find contradictory information ask how are nutrients not building up? then make up your own mind.

G~

Conservation of mas is still achieved. I don't understand why you think it is not. The DSB is to take N03 and convert it to N2 and just vent it off. Not trying to bind it.
Just because things start as solid waste does not mean you need to remove it as a solid (as in algae).

The RDSB is an attempt at removing the aerobic stage a bit, to avoid that H2S pocket creation.

 

[Reefin' Dude]

diffusion only works if there is a difference. the layers of sand also act as a barrier to diffusion. put that red dye in a barrel full of sand, how long does it take for the red dye to actually equalize all through the sand? it will only go into the substrate if the water column is already more saturated than the substrate? why is it more saturated?

so where does the energy needed to convert NO3 to N2 gas comes from? can we say phosphates. remember phosphates are the biological energy source for most organisms. that whole ATP synthase thing. where is the phosphates coming from? of course as we all know phosphates are not off gassed like nitrogen. this is where the conservation of mass comes into play. in order for the DSB/RDSB to function as advertised it must have phosphates available also. where are these phosphates coming from? then where do they go?

P has to be removed. it is not able to be off gassed like carbon, nitrogen, and oxygen. phosphates have to be physically removed. it is P that is at the heard of the problem with the conservation of mass.

H2S pocket creation is formed because of the non-aerobic areas. the whole reason why we want the DSB/RDSB in the first place. these non-aerobic areas can create higher concentrations of CO2. we all know why CO2 is used in calcium reactors. these pockets of low CO2 cause the calcium carbonate matrix to dissolve. when these higher concentrations of calcium carbonate reach higher pH's they solidify creating a solid barrier that provide a true anoxic layer for H2S to form.

again, why have any of this going on in the first place? just remove the waste before it can become inorganic. just remove any unnecessary aerobic areas in the system in the first place. why worry about nitrates anyway? it is not nearly as toxic we are led to believe. the reason why nitrates are blamed for problems is because our inorganic phosphates test kits are not sensitive enough. nitrate is easy to test for. there for a test reading of 20ppm nitrates was associated with a tank crash. when it was in fact that the phosphates are above 0.6ppm that was really causing the crash. it is all about what is limiting. the phosphate level in an oligotrophic environment are at 0.1micromolar, or about 0.009ppm. can your phosphates test read that. i bet it reads 0. if your test kit were to read 0 phosphates, and your nitrate test kit read 10, which nutrient would you blame? for comparison the oligotrophic environment level for nitrate is 0.9ppm. does your nitrate kit read to that resolution?

we as hobbyists have been chasing the wrong nutrient ever since the beginning. it is only in the past 5years or so that we have had access to test kits that are getting closer to the resolution necessary to actually know where are systems are nutrient wise for an oligotrophic system.

G~

 

[Jeff000]

diffusion only works if there is a difference. the layers of sand also act as a barrier to diffusion. put that red dye in a barrel full of sand, how long does it take for the red dye to actually equalize all through the sand? it will only go into the substrate if the water column is already more saturated than the substrate? why is it more saturated?

so where does the energy needed to convert NO3 to N2 gas comes from? can we say phosphates. remember phosphates are the biological energy source for most organisms. that whole ATP synthase thing. where is the phosphates coming from? of course as we all know phosphates are not off gassed like nitrogen. this is where the conservation of mass comes into play. in order for the DSB/RDSB to function as advertised it must have phosphates available also. where are these phosphates coming from? then where do they go?

P has to be removed. it is not able to be off gassed like carbon, nitrogen, and oxygen. phosphates have to be physically removed. it is P that is at the heard of the problem with the conservation of mass.

H2S pocket creation is formed because of the non-aerobic areas. the whole reason why we want the DSB/RDSB in the first place. these non-aerobic areas can create higher concentrations of CO2. we all know why CO2 is used in calcium reactors. these pockets of low CO2 cause the calcium carbonate matrix to dissolve. when these higher concentrations of calcium carbonate reach higher pH's they solidify creating a solid barrier that provide a true anoxic layer for H2S to form.

again, why have any of this going on in the first place? just remove the waste before it can become inorganic. just remove any unnecessary aerobic areas in the system in the first place. why worry about nitrates anyway? it is not nearly as toxic we are led to believe. the reason why nitrates are blamed for problems is because our inorganic phosphates test kits are not sensitive enough. nitrate is easy to test for. there for a test reading of 20ppm nitrates was associated with a tank crash. when it was in fact that the phosphates are above 0.6ppm that was really causing the crash. it is all about what is limiting. the phosphate level in an oligotrophic environment are at 0.1micromolar, or about 0.009ppm. can your phosphates test read that. i bet it reads 0. if your test kit were to read 0 phosphates, and your nitrate test kit read 10, which nutrient would you blame? for comparison the oligotrophic environment level for nitrate is 0.9ppm. does your nitrate kit read to that resolution?

we as hobbyists have been chasing the wrong nutrient ever since the beginning. it is only in the past 5years or so that we have had access to test kits that are getting closer to the resolution necessary to actually know where are systems are nutrient wise for an oligotrophic system.

G~

P has to be removed? Phosphorus?
PO4 has to be removed, but I am not trying to do that with a DSB.

Nitrate is not as toxic as lots of things in the tank, but it is not very good. And without some way to break it down in the tank the only way to remove it is water changes, which is not the greatest way to control it. Can my test kit measure that low, no, but I do have access to some highly specialized equipment if I so choose to measure it.

Diffusion works pretty simple, as the sand bed breaks down the NO3 there is less NO3 in the sand then the water column, so diffusion will work.

I think you are forgetting about actual results as well. Was talking to the owner of the LFS I always go to yesterday, he said they took down a RDSB that was running for 8 years, a 50g drum worth of sand. No H2S smell, no clumps, no black nasty mess. Said for the most part it looked like fairly new sand. The reason they took it out is they didn't think it was doing anything, a week later everything started to look terrible and things started to die. Rinsed the sand, and put it back into the system, a couple weeks later everything started to look better again. This was a 800g system.
Maybe it was just the buffering of the sand that made the difference? If nothing else i am sure the buffering can't hurt.

And finding results just like that can be found all over the place.
Honestly a bit of your post is above my head, it's been 10 years since my last organic chemistry class.

 

[Reefin' Dude]

that is the problem. is that you are not trying to remove P. yes phosphorus or any of its compounds. in order for the breakdown of nitrates one must have phosphates. the more nitrates that are breaking down the more phosphates that are needed to fuel the process. which is all good and all if nitrates are the only process going on, but it is not. the phosphates are building up in the DSB/RDSB because of this. in the process creating a more eutrophic environment. you can not have one without the other. without the bacteria there will not be any breakdown of nitrates. of course with the bacteria come other organisms in the food chain. all eating and dying and pooing in the substrate. creating even more wastes in the DSB/RDSB. again creating a more eutrophic environment.

the problem with diffusion is that the bacteria are also working hard on the nitrates that are being produced by the layers directly above them. diffusion is working, but not in the way you are hoping. the layers just above where denitrification are occurring are performing nitrification on the waste products that they have access to. diffusion is working, but only in that very local area. all of this bacterial activity is creating a diffusion boundary for the all of that nitrate in the water column. as long as there is waste in the area, then the diffusion of nitrates into the substrate will be compromised.

i have done and seen plenty of DSB/RDSB's over my years in the hobby. do they appear to work, yes, but not because of the way we are told. they work because of the increase in the phosphate levels. allowing more resources for the bacteria. it is the phosphate side of the equation that is overlooked by those that promote DSB's/RDSB's.

what was causing the good results was the migration of the phosphates down through the DSB/RDSB. the give and take of nutrients between the bacteria and the calcium carbonate. the calcium carbonate uptake the phosphates. the bacteria remove the phosphates from the calcium carbonate in order to provide energy for converting nitrogenous compounds. the hobby industry focuses on the easy nitrogen cycle, yet does not go into how it actually occurs and what other resources are necessary to perform the process. that would bring out why DSB's/RDSB's do not work long term. the slow accumulation of phosphates. rinsing the substrate of all of that detritus allows new binding sites and new resources to be accessed by bacteria. allowing the substrate to perform as it was before. a great phosphate sink.

please by all means measure it then. i would love to see some good numbers from a home aquarium. we have some numbers for outer reefs it would be good to see how far we need to go though.

G~

 

[Jeff000]

that is the problem. is that you are not trying to remove P. yes phosphorus or any of its compounds. in order for the breakdown of nitrates one must have phosphates. the more nitrates that are breaking down the more phosphates that are needed to fuel the process. which is all good and all if nitrates are the only process going on, but it is not. the phosphates are building up in the DSB/RDSB because of this. in the process creating a more eutrophic environment. you can not have one without the other. without the bacteria there will not be any breakdown of nitrates. of course with the bacteria come other organisms in the food chain. all eating and dying and pooing in the substrate. creating even more wastes in the DSB/RDSB. again creating a more eutrophic environment.

the problem with diffusion is that the bacteria are also working hard on the nitrates that are being produced by the layers directly above them. diffusion is working, but not in the way you are hoping. the layers just above where denitrification are occurring are performing nitrification on the waste products that they have access to. diffusion is working, but only in that very local area. all of this bacterial activity is creating a diffusion boundary for the all of that nitrate in the water column. as long as there is waste in the area, then the diffusion of nitrates into the substrate will be compromised.

i have done and seen plenty of DSB/RDSB's over my years in the hobby. do they appear to work, yes, but not because of the way we are told. they work because of the increase in the phosphate levels. allowing more resources for the bacteria. it is the phosphate side of the equation that is overlooked by those that promote DSB's/RDSB's.

what was causing the good results was the migration of the phosphates down through the DSB/RDSB. the give and take of nutrients between the bacteria and the calcium carbonate. the calcium carbonate uptake the phosphates. the bacteria remove the phosphates from the calcium carbonate in order to provide energy for converting nitrogenous compounds. the hobby industry focuses on the easy nitrogen cycle, yet does not go into how it actually occurs and what other resources are necessary to perform the process. that would bring out why DSB's/RDSB's do not work long term. the slow accumulation of phosphates. rinsing the substrate of all of that detritus allows new binding sites and new resources to be accessed by bacteria. allowing the substrate to perform as it was before. a great phosphate sink.

please by all means measure it then. i would love to see some good numbers from a home aquarium. we have some numbers for outer reefs it would be good to see how far we need to go though.

G~

So what you are saying is that the RDSB is still good, but not really for the reasons people think.
Good is good either way really. I was planning on cleaning the sand every couple years anyways.

I'll get some baseline water tests and then again 3 months after the dsb.
My buddy that can do the tests says the equipment can do parts per billion. He mumbled something about why the parts per trillion wouldn't work or something. So I hope that is good enough.

 

[Reefin' Dude]

it is just a more easily accessible phosphate sink. we need to start thinking of DSB/RDSB as phosphate sinks. the larger the DSB/RDSB the longer it will last before being used up and needing refreshing or replacement. if there is a substrate in the display, then there needs to be a larger more easily replaced phosphate sink somewhere else to help cover the eutrophication that will be going on in the display substrate, especially if the display substrate is not easily cleaned or replaced.

ppb is plenty. the references i have read have all been shown to the ppm, a few into the ppb, but not many.

G~

 

[Jeff000]

it is just a more easily accessible phosphate sink. we need to start thinking of DSB/RDSB as phosphate sinks. the larger the DSB/RDSB the longer it will last before being used up and needing refreshing or replacement. if there is a substrate in the display, then there needs to be a larger more easily replaced phosphate sink somewhere else to help cover the eutrophication that will be going on in the display substrate, especially if the display substrate is not easily cleaned or replaced.

ppb is plenty. the references i have read have all been shown to the ppm, a few into the ppb, but not many.

G~

Ok.

Can you explain phosphate sink in more laymen terms? I had to google a lot to figure out what was being said.
Also do you have a theory as to how much sand would be needed and how long it should last ?

 

[Reefin' Dude]

the phosphate sink is just a place where large amounts of phosphates are bound. in a healthy system this is always going to be temporary. phosphates are going to be moving constantly between bacteria, calcium carbonate, and other organisms. phosphates are a hot commodity, especially inorganic (water soluble). inorganic phosphates will bind readily to calcium carbonate, the same as GFO, and other phosphate binders. the difference is that bacteria are able to remove them if other resources are also available to feed the bacteria. a new substrate will have some new binding spots available on it. the inorganic phosphates will bind to these. then the bacteria start growing, and taking off the phosphates in order to perform other functions. to simplify lets say denitrification. these bacteria will live, then die. being so small they migrate slowly down in the substrate. then other critters show up in the substrate allowing detritus, the poo from these other critters, and the bacteria to migrate more efficiently down through the substrate. these new empty binding sites allow more inorganic phosphates to bind. it is this process that keeps phosphates low enough for us to keep corals in a close to oligotrophic conditions. we are relying on the calcium carbonate and bacteria to create a phosphate sink. this works fantastic for as long as the substrate does not get chocked out by detritus, critter poo, and bacterial flock. low flow areas create the ideal settling point for detritus, this can quickly clog up a substrate behind LR, which is also performing the same processes, but since LR is surrounded completely by moving water the bacterial flock is removed from the LR constantly. LR is able to clean itself and process phosphates indefinitely. not something that a substrate can do without good cleaning. in most cases it is just easier to replace the substrate because the grain size of the substrate was to fine to allow easy siphoning.

it seems that in a normal display system the sand last about as long in years as it is deep in inches. this is for an untouched substrate, or a substrate that has large areas that can not be touched. you can read on most any forum and you follow algae questions coming from tanks that seemed fine for a good amount of time, then they start to have algae issues. there are a ton of variables, but this seems to be a good starting guide.

this goes back to why have a phosphate sink at all in the system? once you have one, then it becomes an arms race to keep the sink in the display from becoming ugly, so people add more and bigger sinks to counter. if you remove the detritus, critter poo, and bacterial flock before it can decompose create inorganic nutrients, then the size of the phosphates sink can be significantly smaller. the LR itself will do.

G~

 

[Maivortex]

Seems like this thread goes in circles. Low flow and detritus is good in a RDSB but bad, clogs up DSB? Its not clear why phosphate is needed to process Nitrogen. Are you saying 0.009 ppm of phosphate is a concern?, C'mon man.....

 

[Reefin' Dude]

what do you need clarification on. low flow for collecting the detritus is good in a RDSB because it is drawing the sources of phosphates to an area that is far easier to clean. can it clog up the DSB/RDSB faster, yes, but it is better there than in the display where it is much harder to remove it.

organisms need phosphates in order to perform any biological function. they use it for energy. i posted a link to ATP Synthase to read up on. bacteria are converting the various nitrogenous compounds, how? what are the bacteria feeding on in order to perform these various synthesis? i know the hobby has ignored phosphates for years because it was difficult and test kits just were not up to the task. they still are not, but they are getting closer. and yes an inorganic phosphate level of 0.009ppm is a problem if the aquarist is interested in keeping an oligotrophic system.

feel free to post references for an acceptable inorganic phosphates level. in this thread i have posted a fair amount of references for how eutrophication is causing the destruction of reefs. in these papers are levels of nitrate and phosphates that seem to be limiting for algae growth. just because your test kit can not read a level of 0.009ppm does not mean that it is not there and causing a problem. when someone says they have a phosphate level of 0 what does it mean. 0, 0.0, 0.00, 0.000? a test kit that can only read 0.01 will not show a problem if the limiting level is 0.009. it is beyond the resolution of the kit. this is why nitrates have been given the bad rap. they are far easier to test for, their limit for algae growth is higher, and being a waste product will tend to increase in parallel with the phosphates. when tanks crash the easy test showed nitrates as the problem, when the fact is both phosphates and nitrates were, and both were way beyond limiting for algae growth. now that we are getting better test kits we can become more specific about what is limiting. even nitrates do not become limiting until into the 0.1ppm range. (i will need to do a micromolar conversion on this to be sure, but i think that is right). does your test kit read 0.1ppm nitrate?

the only indicator that nutrient levels are no longer limiting to algae growth is if algae is growing (this is again for those emulating oligotrophic environments).

we have been using calcium carbonate for years as a phosphate binder. we just were told that it was doing something different. it does not make what was going on any different. Rule#1 phosphates have to be exported, they can not be off-gassed. if phosphates are not exported as fast as they are imported (minus organic uptake of those critters you actually paid for and want) then the system is becoming more eutrophic and eventually the levels will get above those limiting for algae growth.

feel free to do independent study on phosphates and get back to us about what you think is going on. look up calcium carbonate as phosphate binders, where phosphates are mined, where is the greatest amount of phosphates located on Earth, why is calcium carbonate used as ant-acids, and in dialysis machines. look up how eutrophication is damaging the reefs. what is eutrophication? i am not giving out any information that is not hard to come by. i just needed to be pointed in the right direction. if you would like to find threads on RC about all of this, then look up posts by Bomber. they would all be before 2005 though, but they go farther in depth than what i can do.

G~