PO4 always high

[gchaney]

Not sure if this is the right tab but I will give it a try.
I have a 125gallon mixed reef tank with a 55 g sump/refugium. My issue is my PO4 is always around .20 per the hanna checker and I have verified it with several other test kits. I am running an etss 800 skimmer I have macro algae in the sump on a reverse light cycle. I have even cut back feeding to once every four days I test my water change water and its always zero. I have tried GFO and the brightwell PHOSR stuff and even with those it only goes down to about .17.

Does any one have any idea where this PO4 might be comming from or what I could do about it.

 

[ivans75]

tagging along on this one. I've got a system that is alwaaaays low on phosphate and a system who always have similar p04 contain like yours. (.14) I dose carbon on both and dont run gfo at both. The one thats low on po4 is zeovit system tank and the other thats got .14 po4 is dsb system with biopelet. But both tanks are performing well, corals are expanding nicely. Both got 0 nitrates but the .14 tank get cyano sometime.

 

[windyridge]

What kind of live rock do you have? Maybe they are leeching phosphates?

 

[ivans75]

i dunno if a fully cured live rock can leach phosphate...i always use a fully cured live rock even if I get a fresh live rock from the sea, I always take sponges off

 

[Randy Holmes-Farley]

Not sure if this is the right tab but I will give it a try.
I have a 125gallon mixed reef tank with a 55 g sump/refugium. My issue is my PO4 is always around .20 per the hanna checker and I have verified it with several other test kits. I am running an etss 800 skimmer I have macro algae in the sump on a reverse light cycle. I have even cut back feeding to once every four days I test my water change water and its always zero. I have tried GFO and the brightwell PHOSR stuff and even with those it only goes down to about .17.

Does any one have any idea where this PO4 might be comming from or what I could do about it.

Unless this is an aquarium where you are not feeding anything at all, the primary source of phosphate is almost always fish foods, and folks rarely need to look any further than that. All fish foods contain a lot of phosphate.

There can also be a secondary source (such as phosphate bound to the live rock or the use of tap water for top off). Once phosphate is high, there will be phosphate bond to the rock and sand, not matter how pure it was when it went into the tank, and as you try to bring down phosphate, you will have to strip phosphate out of that reservoir as you go.

In any case, if you measured phosphate values are correct, more GFO replaced more frequently will bring it down.

 

[gchaney]

Glad to see a tag along as Ivan said my coral and all are doing great I proba ly would not even be chasing this if it wast for the cyano on my sand bed. My rock is a conglomeration but it all came from otger established tanks etc. None of my rock has bee. In a tank for less than two years.

 

[gchaney]

Unless this is an aquarium where you are not feeding anything at all, the primary source of phosphate is almost always fish foods, and folks rarely need to look any further than that. All fish foods contain a lot of phosphate.

There can also be a secondary source (such as phosphate bound to the live rock or the use of tap water for top off). Once phosphate is high, there will be phosphate bond to the rock and sand, not matter how pure it was when it went into the tank, and as you try to bring down phosphate, you will have to strip phosphate out of that reservoir as you go.

In any case, if you measured phosphate values are correct, more GFO replaced more frequently will bring it down.

I was pretty sure it was comming from the food just didnt think that much gues I will try more gfo.

 

[ivans75]

Randy, the one that has .14 phosphate only have 3 fish in it, 2 damsels and 1 black nemo. I don't feed my fish much thats for sure. And I dont use pellets, only frozen from live mysis shrimp. So my option is that something is leeching phosphate but what are they. I used LRs from the same source for both tank. I never use tap water ever again. PO4 in this tank is never get higher than 0.2. I wanna try coral snow on this tank see if it can get rid of my cyano or perhaps get rid of those leeching po4

 

[Randy Holmes-Farley]

Any rock with dead organisms on it will leach phosphate, but in general, it takes relatively little fish food to reach 0.14 ppm.

 

[pscott99]

Any rock with dead organisms on it will leach phosphate, but in general, it takes relatively little fish food to reach 0.14 ppm.

Randy, again thanks for all that you do. How much fish food is considered a little, for say 60gal of total water or how ever you want to put it. My PO4 went from .11 to .06 last week. Continue to push GFO. The OTP said feeding every four days holy crap.