Rowaphos will absorb PO4 but wont release it. We don't rinse or filter Rowa when we add it & the sump has a nice covering of the stuff. It does cloud the water for the first day, but the skimmer gets rid of it. I didn't see the point of rinsing away an expensive product for no reason other then "it will cloud your tank" There are no ill effects in the tank since doing it this way. Personally, I wouldn't worry about it. Get it out over time when your playing in the sump. :)