FAQ: You claim that Seachem PhosNet™ has a high capacity, but Company X claims that their GFO has a capacity that is many times higher. Is this false advertising?

It is actually quite easy to change the apparent capacity of a GFO during testing. If the capacity of a GFO is tested at an extremely low pH with a phosphate concentration that is much higher than the media can completely absorb, the media will temporarily absorb much more phosphate than it would under ordinary aquarium conditions. We have no interest in artificially puffing up our numbers, so the capacity we have listed is the amount of phosphate that the media can completely remove (without releasing back into the water) in a pH of 8.4.