How quickly should you raise phosphates in a reef tank?

ODD

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Hello,

I have been running a 180g+ 60 gal sump) acropora reef tank for almost a year now, I've had frags for a few months and some do better than others, I have some milleporas that have paled over the past months. A while ago, I've come to the conclusion that my phosphates were the issue. I was reading 0 ppb (yes, ppb).

I've then decided to feed more (3x daily) to see if phosphates rose. I kept on doing so for a few weeks and... no change.

So after some digging I decided to use Seachems '' Flourish, Phosphorus'' ( https://www.seachem.com/flourish-phosphorus.php ) And after conversion I decided to dose 1,7ml to my aquarium (0.17ml per gallon, I stuck on the lower end for the x10).

This initial dose was this morning. I came back to it three hours later to test and... still 0 ppb phosphate. So I dosed another 1,7ml and... three hours later still 0 ppb.
However, I DID notice that there seemed to be alot more brown algea on the glass and, my pale milleporas seemed to have gained more colour. Which would be surprising in just a day so I may be mistaken.
Before the question is asked:

pH is 8,1 (night) to 8,4 (day)
Dkh is a stable 8,5-9
Ca is 450
MG is 1300
Nitrates are 13 ppm (Probably because of the abusing feeding, I will get it back down to below 10.)


Now I wonder:

1) how much should I add daily and how quickly?
I was planning on adding 2ml in the morning, testing it in the evening and adding another 2ml until I see phosphate appear on the test and then slow down until I get to 0,03ppm ish. Is this wise?

2) the bottle says phosphorus, and I wonder : does it need to decay before my test kit (hannah checker ULR) can pick it up?


Thanks!
 

e34stx

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i would also like to hear what people think about adding amount and frequency. i have been dosing sodium phosphate 1ml to 2ml daily,3g/400ml on my 150g display for 4 days and still the hanna ulr phosphorus reads 0. i was thinking of either increasing the solution or dosing more.
 

Randy Holmes-Farley

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When phosphate has bottomed out, it can take very large amounts to bring it back into range due to binding to rock and sand.` Just keep dosing until it comes back on scale.

In the future, I'd recommend food grade sodium phosphate. It has a purity assurance the Seachem product lacks, and will be less expensive.
 
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ODD

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When phosphate has bottomed out, it can take very large amounts to bring it back into range due to binding to rock and sand.` Just keep dosing until it comes back on scale.

In the future, I'd recommend food grade sodium phosphate. It has a purity assurance the Seachem product lacks, and will be less expensive.
Is there a pace for it or I can dose until it shows up?
 

Randy Holmes-Farley

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Thank you Randy, should I expect a delay for phosphorus to decay to phosphate?

This morning I was reading 4 ppb. This was after dosing 6,7 ml total

I presume you are dosing phosphate, not phosphorus which burns on contact with water or air . So there is no delay.

 
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ODD

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I presume you are dosing phosphate, not phosphorus which burns on contact with water or air . So there is no delay.

Haha... my bad I missunderstood the bottle. Thank you.
 
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