Originally Posted by Professor Myers

For Corals you'll want to keep PO4 below .3 ppm The lower the better whether it's toxic or not is subjective. More importantly it contributes to brown algae and chokes out the coral. Best media I've found so far is Rowa Phos in a fluidized column. I don't do this schtick any more ! P.S. Never ever use this in a planted tank unless you sincerely want to know what will happen. HTH. Prof M