Phosphates

[five.five-six]

1.2-2 pounds of live rock per gallon solves everything!

[ERIC85854]

Originally Posted by five.five-six

1.2-2 pounds of live rock per gallon solves everything!

No it doesn’t. Getting rid of the sand helps more.

[pisanoal]

Originally Posted by ERIC85854

No it doesn’t. Getting rid of the sand helps more.

How do you figure?

[pisanoal]

Originally Posted by Pslreefer

I thought about that as my nitrates are very very low


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I would DEFINITELY be dosing nitrate then. Dose a little a time and watch your phosphates fall. I wouldn't mess with GFO until then. Just don't get crazy as you will likely start having algae issues.

There are lots of threads on this, and i've observed it in my tank several times over. Search for "dosing nitrates to reduce phosphates".

[ERIC85854]

Originally Posted by pisanoal

How do you figure?

Sand traps organic matter which then breaks down and increases nutrient levels.

I went from 30 NO3 to 1 over a couple months by just getting rid of the sand bed.

[pisanoal]

I know that argument, but to say that its going to solve this problem makes a lot of assumptions, a lot of which are unsupported thus far in the conversation.

I have a sand bed and have to dose nitrates and phosphates so I have some nutrients in my 18 month old system. I also have to feed like crazy. If I dont dose every other day, my nutrients drop to 0.

So how would removing this sand bed solve the OP's phosphate problem?

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[ERIC85854]

Originally Posted by pisanoal

I know that argument, but to say that its going to solve this problem makes a lot of assumptions, a lot of which are unsupported thus far in the conversation.

I have a sand bed and have to dose nitrates and phosphates so I have some nutrients in my 18 month old system. I also have to feed like crazy. If I dont dose every other day, my nutrients drop to 0.

So how would removing this sand bed solve the OP's phosphate problem?

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I don't know what his specific problem is caused by. His tank is probably too new so I doubt it's the sand. All I know is throwing a whole bunch of live rock in there is probably not going to change anything. Addition of rock never did anything detectable to lower my nitrate/phosphate levels. It will definitely help nitrification if there are problems with ammonia, nitrite.

He is probably adding too much food and other crap to his tank. Phosphate level will go sky high before the nitrate has a chance to catch up. It might also be coming from his water supply.

[bertoni]

I ran a tank with a coarse substrate (crushed coral) for a while. The crushed coral seemed to trap organic debris, which then decayed and released mineralized nutrients, phosphate, and nitrate, into the water column. Replacing the substrate with very fine sand fixed that problem. Even a coarser grade of sand can trap a lot of debris, and I suspect a sufficient organic load can contaminate even very fine sand. What happens in any specific tank will tank some examination and thought to understand. I don't think there are any guarantees that you can make without looking at the substrate in question.

[Pslreefer]

Definitely not sand as it’s only about half inch deep and it was caribalive punk fiji.

Also I never had po3 above 5, even after cycle, it is always high po4.

I’ll prolly run some gfo and reduce feedings since I did feed heavy and go from there.

I like running high nutrients but just wasn’t sure if too high of po4 will rtn my sps, as I have lost some, but typically a few days after a delivery from wwc and usually only 1 our if the bunch.


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[ERIC85854]

Originally Posted by Pslreefer

Definitely not sand as it’s only about half inch deep and it was caribalive punk fiji.

Also I never had po3 above 5, even after cycle, it is always high po4.

I’ll prolly run some gfo and reduce feedings since I did feed heavy and go from there.

I like running high nutrients but just wasn’t sure if too high of po4 will rtn my sps, as I have lost some, but typically a few days after a delivery from wwc and usually only 1 our if the bunch.


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.6 seems excessive but mine have never been that high so I can't speak from experience. I would shoot for .1 or lower if you're having problems.

[Timfish]

Part of the confusion comes from a paper referenced by Randy Holmes-Farley that found very low levels of bisphosphonate inhibited calcification. More recent research found "Bisphosphonate has been considered to inhibit calcification but not photosynthesis in corals. We show that bisphosphonate may not inhibit formation of amorphous calcium carbonate and that the inhibition of calcification is possibly illusory" Research that's been around for a long time but overlooked or ignored by many is PO4 levels on reefs on average are .13 mg/l and upwelling can raise PO4 levels to as high as 2.0 mg/l. Here's a good video discussing PO4 levels in aquariums by Richard Ross from the Stienhart Aquarium in CA: https://www.youtube.com/watch?v=ZRIKW-9d2xI
Phosphate is critical for corals if they are not being fed and their ability to use nitrogen is limited by it's availability. And research by Southampton University in England found PO4 deficiency reduced coral biomass and promoted bleaching.

[pisanoal]

Originally Posted by Pslreefer

Definitely not sand as it’s only about half inch deep and it was caribalive punk fiji.

Also I never had po3 above 5, even after cycle, it is always high po4.

I’ll prolly run some gfo and reduce feedings since I did feed heavy and go from there.

I like running high nutrients but just wasn’t sure if too high of po4 will rtn my sps, as I have lost some, but typically a few days after a delivery from wwc and usually only 1 our if the bunch.


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If you have 0 nitrate, try dosing nitrate before using gfo. It sounds like you are nitrate limited.

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[Aliasger789]

GFO is a very good idea, although i haven't tested on my tank. I have 5000 Gallon fish only tank which has been converted to reef recently. My phosphate levels are about 1.2ppm and have been running for almost 5 months. I have a refugium which has given me some good results. It will still go low slowly.

[Pslreefer]

Happy to report after my 4 day trip to the parents for Christmas I came back to find the po4 down to .5! With this info I feel I can let it come down naturally through export from my cheato and filter feeders in the cryptic sump and less feeding.




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[ERIC85854]

Originally Posted by Aliasger789

GFO is a very good idea, although i haven't tested on my tank. I have 5000 Gallon fish only tank which has been converted to reef recently. My phosphate levels are about 1.2ppm and have been running for almost 5 months. I have a refugium which has given me some good results. It will still go low slowly.

GFO has done more harm than good for me. Even only 3 TBSP for 50 gallons.

[bertoni]

Less feeding often is the easiest solution to nutrient problems. Fish can be very good at begging.

[reefgeezer]

Originally Posted by Pslreefer

How high is too high before it becomes detrimental to sps?

Inorganic phosphate is what your test kit reads. I have no idea if there is an absolute number that is too high for SPS corals... BUT... IMO... keeping phosphates at about .05 ppm as reported by a good Ultra Low Range Colorimeter is preferable. I have too much time on my hands right now so here's the thought process that yielded my preference.

IMO, it is safe to say that some inorganic phosphate is necessary for biological functions. Again IMO, excessive inorganic phosphate can cause problems such as algae outbreaks. I'm not a biologist so I don't "know" how much is required. The level where necessary becomes excessive is obviously debatable.

Some corals can get the phosphate they need from organics and bacteria they feed on. The organics and bacteria contain phosphates that your test kit doesn't count. Their formation or propagation reduces inorganic phosphate.

I suppose some corals or their symbiotic algae may need to uptake (absorb) some inorganic phosphate directly. I think that even low levels of inorganic phosphate indicate that there is more than enough available. It means that all the organic compounds that can form have been formed and that all the needs for inorganic phosphate of the corals and other organisms in the system have been met. I also suppose that some necessary biological activities might be limited if inorganic phosphate levels are 0.

The colorimeters I use has an accuracy of about .04 ppm. I want to make sure there is some inorganic phosphate, so I shoot for .05 ppm. That gets me in the range of .01 to .09 ppm.

[Timfish]

FWI you PO4 level is in the range of normal for reef systems. Be very careful about lowering PO4. It's essential for corals and too low really screws up a reef system potentially giving algae the upper hand as it can out compete corals for phosphate. Watch Richard Ross's video and look at this paper on the effect of phosphate deficiency on corals grown in aquariums for several years.

Additionally there is contradictory research on the effect of bisphosphanate on corals growth and it's effects on calcification. "We show that bisphosphonate may not inhibit formation of amorphous calcium carbonate and that the inhibition of calcification is possibly illusory"

[bertoni]

I agree that it's worth being careful with the phosphate level. Overdoing GFO seems to be able to cause problems. I don't think it's necessary to have measurable phosphate in a tank, but having a bit showing up on a meter is a good sign that phosphate isn't dangerously low.

[Pslreefer]

Agreed. I like a higher nutrient tank, as I’m a believer that it is better for overall health, growth, and color of corals, then an ulns system.


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[Pslreefer]

I was/am just unsure of how high is actually too high.


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[bertoni]

I think we all are. The issue seems to get less and less clear over time.

[Timfish]

My own experience I've seen many corals seem very happy at 5.0 mg/l PO4.
DO NOT TAKE THIS AS AN ENDORSMENT ON MY PART TO KEEP PO4 AT THIS LEVEL. THE AVERAGE ON REEFS IS .13 MG/L.
But having kept the same corals for decades we need to expect each species, genotype and variety to react differently to the same conditions. And since corals have demonstrated "memory" for environmental conditions we need to take into account the history of a clone line as well. And yes I know currently this unrealistic.

I think part of the reason for the confusion about PO4 is decades ago it was assumed the typical reef had much lower levels than what we now know they do. Both Adey and Holes-Farley referenced sources that gave a typical reef PO4 at .003 mg/l when we now know it's actually much higher.

A second problem shown by research at Southampton Univerisity in England (linked to above) is the RATIO of nitrate to phosphate is important and an imbalance promotes bleaching. With varying levels in our systems we don't know what this ratio is so a given PO4 level for one aquarist MIGHT be a problem for another aquarist.

[reefgeezer]

What do SPScorals do at .13 ppm or higher of phosphate that they can't do at .03 ppm? I suppose .13 isn't that high, but I'd be uncomfortable keeping my tank any higher. It may or may not effect the corals but it does promote pest algae.

[bertoni]

Higher levels of phosphate might inhibit calcification, but that's not clear. There is some evidence that it might, and other evidence that it doesn't. I would watch the corals, and change things only when growth or coloration need improvement, whatever the conditions are, most likely, although I have a basic bias towards keeping the phosphate level low, down near a measured zero on hobbyist test equipment. Too low apparently can be bad, though, so I try not to be pedantic about it.