Are you running phosphate remover in a reactor? If you are just running it passively it probably isn't working well. Also phosgard is not the best IME. An iron based GFO used in a reactor will work much better. IME excess phosphate come from an old sand bed, old rock, or an an RO/DI that's not working properly. Of course it can come from overstocking but that's rarely the case if you have a good skimmer and phosphate reactor with GFO. I have seen where people removed excess nitrate with a DSB in a bucket. A small fuge will do very little to remove excess nutrients and if not cleaned regularly can even make them worse IME.