High PO4 and Phosguard efficiency

[Acroporaaddict]

About two months ago, I had a dinoflagellate attack. I increased my nutrients via dosing and fed heavier. This caused my PO4 to rise to .28ppm. The dinos are gone, and my acropora took a significant hit in color. Most are slightly brown or losing their vibrant coloration. I added Phosguard to a media reactor according to the manufacturers suggested amount. After 24 hours I've noticed no change in PO4 levels via Hanna checker. I emptied out old Phosguard thinking it may have been depleted already. I let the new Phosguard run in the reactor for one hour then measured the reactors output to see if there was a decrease. The PO4 level from the reactor output using one hour old Phosguard is .26ppm. Should the Phosguard be removing more than .02ppm PO4 from the water? I seem to recall when I used BRS GFO, the reactor output would measure at 0ppm PO4. Is Phosguard really that inefficient?

 

[jtl]

I have never used Phosguard but I just knocked down my PO4 from 0.061 to 0.015 in 24 hours using GFO in a reactor.

 

[ckalupa]

The phosguard instructions say to give it 4 days in operation then test. Also it cautions not to have it tumbling on to itself (like GFO would). I use it in a zipper bag in the sock and see results overnight (I also don’t use the full amount). 1/3 cup per 50 gallons. It’s not a rapid strip process from my experience.

I have also seen phos as high as .25 at times when not paying attention but not witnessed brown out. Each tank is different though.