should I stay with a cartridge filter or switch to a sand filter pump. I've heard every time you backwash you lose 2-3 inches of water and when I add water it adds iron back in which makes water orange again and then I have to battle getting the iron back out. Seems like the metal out/ metal magnet / stain remove all those things only last for a while especially if I were to keep adding in 2-3 inches of iron water every week. when would it end? presently I have an 18' x 52" intex ultra frame pool with a 2500 gph cartridge filter pump, is there a bigger cartridge filter pump for the pools? should I go with the 2650 gph sand filter? The reason I am asking is because my water is still green even after a month of shocking and raising chlorine levels to way high (orange on tester instead of yellow) I've put 2 bottles of seaklear stain remover/preventor (pool guy said that would take the iron out, and it does seem to make it clump together so the filter can grab it) and my pool is still green so I thought maybe I need a bigger/different filter/pump how can I get a clear pool like everyone else has? my filter is still rinsing orange/brown stuff off (assuming that is the iron) but why is the green not going away? any help would be appreciated.