Dosing Phosphorous.

Uncle99 · Jul 3, 2020

65g, 40 month mature mixed reef with the following parameters.
Temp 78
Salinity 1.0255
Nitrate 20ppm
Phosphate 0.02
Mg 1360
Alk 11.5
Ca 465
Iodide 0.03

For Fish, BT, YT, clown pair, Anthais, RG, Mandarin.
Lots of mixed coral, see below.

In order to maintain trace phosphate level I need to dose 1ml phosphate every day, otherwise, it zeroes out.
I am getting results from my Hanna ULR of (0.022) and Salifert (0.03) after the 1ml dose, then, in 24 hours later, Zero n both.

Does that seems normal? I am I to conclude that corals are using up the phosphate?

Any comments welcome.

LRT · Jul 3, 2020

Uncle99 said:
65g, 40 month mature mixed reef with the following parameters.
Temp 78
Salinity 1.0255
Nitrate 20ppm
Phosphate 0.02
Mg 1360
Alk 11.5
Ca 465
Iodide 0.03

For Fish, BT, YT, clown pair, Anthais, RG, Mandarin.
Lots of mixed coral, see below.

In order to maintain trace phosphate level I need to dose 1ml phosphate every day, otherwise, it zeroes out.
I am getting results from my Hanna ULR of (0.022) and Salifert (0.03) after the 1ml dose, then, in 24 hours later, Zero n both.

Does that seems normal? I am I to conclude that corals are using up the phosphate?

Any comments welcome.

Following along here as I'm having same issues.
I recently ran my nitrates to 0 but had my phosphates sitting around .025. Overdosed my Nitrates with faulty kit. Steadily got Nitrates back down to around 15ppm now. But phosphates bottoming out zero now. Been dosing phosphates with salifert to detectable levels but closer to .03.
Do Nitrates use up the phosphates?
Should I be dosing more considering my Nitrates are higher than normal?
Really wish I could wrap my head around this.

rmurken · Jul 4, 2020

What’s the concentration of your phosphate supplement?

I am also having zero PO4, but am scaling back the photoperiod on my chaeto. You’ve got a lot more stuff in your tank than me so could be a different situation. But PO4 is tricky—it can bind to your rock and become invisible to a test kit, even though it’s maintaining some sort of equilibrium between the rock, the water, and whatever organisms consume it.