My pool is about 15' x 30' in ground concrete. I don't have the pump model, but i'm about to go outside and I will get it then and update. My pool is clear right now. If I leave the cartridge out; the pump runs perfectly and I could leave it all day. When I put the cartridge in that I just cleaned, however, the pressure and everything is good, but within 30min-2 hours; the pressure is right at 20 and the circulation is bad. I rinse this cartridge off with a garden hose attachment multiple times a day. When I pull it out; it's not even that dirty. I have a cartridge bath, and I have used dishwasher powder multiple times like I read somewhere to do. That didn't help. I used hydrochloric acid, because I read calcium can build up on the cartridge, that didn't help either. I just bought some TSP from home depot and I am about to try that now. I have a feeling that won't work either and I will still be puzzled. Any help is greatly appreciated. I just bought this cartridge not even 2 months ago, so it's still in good shape.
edit: pump is a Hayward SP2707X10un