I have a GAME 4510 SandPro 1/2 HP sand filter running with my Intex 18 x 48 pool. I'm pretty sure this is plenty of pump. The cartridge filtration system that came with the pool last year was terrible. I had mutiple algae explosions and it was very frustrating. Right now I'm running both the sand filter and the cartridge filter (separate from each other) at least 11 hours a day. Am I running these pumps too much? Do I need both of them? Does it hurt to run both (besides my electric bill). The cartridge filter pulls in water from the middle of the pool while the sand filter is pulling in water from the very bottom. Any help would be appreciated.