After reading the forums for the past year, I need some help that I can't quite figure out from previous forum posts.
Installed a doughboy 18'x34' with ~7' deep end (~21K gallons) last year, and it came with a sand filter (silica II) and a 2hp pump (20amp 115v). (1) 1.5" return line, (1) 1.5" suction line. Run the pump eight hours a day. Lines will be within 10' of outlets/inlets (ports?)
I want to replace the the sand filter and pump with a cartridge filter and more efficient pump. From what I've been reading, I should go with something bigger than the XStream 150, and this is where I get confused. If I go for a larger filter (425?), will I not be able to give it the pressure it needs? The more I read about the GPM and Design Flow Rate, the more I get confused.