Also heard that if its organic you can try and rub a trichlor puck/tablet on it, so I'm gonna try that to. I'm also hooked on the DE powder lol, I add alittle after each backwash just to help keep the water really clean, it seems to work. Before I put the valve in between the pump and filter I never had to backwash because the pump just forced the water thru the sand without filtering it, now it's throttled back and my pressure actually rises and requires backwashes lol. Just another example of the awesome advice from the pool forum