High P and low PO4 - what to do?

[EmptyWallet]

Hi Folks,

I've read what I could find on the topic of P vs PO4, including as always, a brilliant article from Randy
https://www.advancedaquarist.com/2002/9/chemistry

I won't pretend to understand the difference entirely, but how did I get to a position of high P (28 ug/l) and low PO4 (0.03) and what can I do about it? I suspect now high P is the root cause of my GHA outbreaks, well the root cause of the P is the root cause of the GHA lol.

I have an oversized deltec skimmer, a fuge pumping out chaeto under Kessil H380, removed all the substrate and have cut my feeding down as low as possible. I run GFO and struggle to keep detectable PO4 above zero (Hanna), yet P increased from 5 to 28 in the past 6 months according to triton ICP ???

Thanks,

 

[sghera64]

Are you using the Hanna ULR Phosphorus meter or the phosphate Checker?

The ULR reports results are expressed as ppb (approximately ug/L) Pi (Pi is short for inorganic phosphorus). If you multiply that number by 3.06 you convert Pi to PO4 (in ppb or approximately ug/L).

I believe Triton’s ICP-OES is measuring each element individually (Pi and not PO4).

 

[EmptyWallet]

Thanks. I'm using the phosphate checker and the confusion came from thinking my P and PO4 were out or proportion. But I think you just helped me realise that is not the case as converting my PO4 mg/l to P ug/l (by x 3.06) is roughly the same number and therefore in the correct proportion.

THANKS!

 

[sghera64]

Thanks. I'm using the phosphate checker and the confusion came from thinking my P and PO4 were out or proportion. But I think you just helped me realise that is not the case as converting my PO4 mg/l to P ug/l (by x 3.06) is roughly the same number and therefore in the correct proportion.

THANKS!

Good to hear.

Also, I believe the Hanna Phosphate Checker reports results in ppm-PO4. So 0.033 ppm-PO4 is 33 ppb-PO4 (or ~33 ug/L), which is about 9.8 ppb-Pi.