PO4 deficit

kutcha · Oct 1, 2020

nereefpat said:
Which one? What number (HI736?)?

@nereefpat it is a 713 i bought it in 2013

nereefpat · Oct 1, 2020

kutcha said:
@nereefpat it is a 713 i bought it in 2013

That isn't the right one, unfortunately. It isn't sensitive enough. That's the low range for fresh and salt.

You want the ultra low range (I know, the it's a silly name) phosphorous. 736. Or apparently they now make a ULR that reads in ppm phosphate. It looks like that one is 774. I will always recommend the ppb phosphorous one.

With any other kit, you can't detect the low levels in a reef tank that has natural seawater parameters.

shakygator · Oct 1, 2020

nereefpat said:
You want the ultra low range (I know, the it's a silly name) phosphorous. 736. Or apparently they now make a ULR that reads in ppm phosphate. It looks like that one is 774. I will always recommend the ppb phosphorous one.

The 774 is supposed to convert the numbers from 736 for you, as well as extend the timeout period people often have issues with.

I've always had a 713 as well and it would consistently read 0. Just got my 774 this week to see if anything is detectable (ICP last month showed 0).

jda · Oct 1, 2020

This has nothing to do with this, but if the unit times out, then run both vials back through without the timer. The numbers are always close.

schuby · Oct 1, 2020

@kutcha . when you say you're running an Algae Turf Scrubber and a fuge, do you mean that you have macroalgae in your refugium in addition to the ATS?

kutcha · Oct 1, 2020

schuby said:
@kutcha . when you say you're running an Algae Turf Scrubber and a fuge, do you mean that you have macroalgae in your refugium in addition to the ATS?

@schuby yes i have my skimmer then a fuge with chaeto and bio bricks then in the return chamber i have a pump for my ATS that water falls back down into the fuge area

Ike · Oct 1, 2020

SPR1968 said:
If my Hanna reads zero I’m delighted because it has a margin of error of +/- 0.04 I think, the one I use anyway, and you really need to keep phosphate below 0.03 to avoid many of the issues you read about.

I use rowaphos and ‘heavy’ to keep it locked down.

If your feeding etc., the reading is unlikely to be absolute zero and you only need a tiny amount for cell formation etc.

So if everything is ok, I would leave well alone and certainly don’t actively try and increase it.

Couldn't disagree more. With all the carbon dosing and weird manipulations of nutrients go through this has become a problem for a lot of people, especially those that keep fast growing SPS. P is essential for life and if it's limited your growth will be dismal and some stony corals will suffer. In my last tank I had many issues manitaining PO4 above .04, which for my checker seemed to be about where things started getting bad and corals suffered. This was clearly and obviously repeatable, yet still anecdotal.

To the OP, add some fish if you can, feed more and start eliminating things that will strip PO4 from the water if it doesn't improve. Unfortunately, some corals never recover or take months to recover and grow again, but that's mostly with acropora. Removing the chaeto could also be a good move.

kutcha · Oct 1, 2020

Ike said:
To the OP, add some fish if you can, feed more and start eliminating things that will strip PO4 from the water if it doesn't improve. Unfortunately, some corals never recover or take months to recover and grow again, but that's mostly with acropora. Removing the chaeto could also be a good move.

@Ike I have
2 fire fish
2 mocha clowns
2 Dalmatian mollies
1 yellow tang
1 melanaruss wrasse
1 lawnmower blenny
1 mandarin
1 pink anthia
1 sandsifting goby

I worry about my pod population in the fuge area if I remove the Chaeto.

schuby · Oct 1, 2020

Chaeto and ATS do the same thing: remove/consume phosphate, nitrate, and iron. Having both on the same tank is unusual. To stop removing too much phosphate, you can turn the ATS off and/or harvest some of the chaeto (smaller size remaining for pods).