27,000 gal 3M Quartz Plaster/Gunite inground pool, Bleach. I've had a Hayward SwimClear C4025 cartridge filter (four cartridges) for 10 years now and have probably replaced the carts 3 times. I'm having issues again with the cartridges, even though they look new after washing with a garden hose, the pressure steadily rises over a couple hours. I'm thinking rather then spend $200 again on cartridges, maybe its time to try a new filter. It seems the DE filters offer the best filtration however require more maintenance then a sand filter. The sand filters seem a little more economical as well therefore, I'm kind of leaning towards sand.
What should I get? And how do you size the DE and Sand filters for my application? What type of control valve should I look for? What else do I need to know?
Any feedback would be greatly appreciated!