I have a Hayward DE filter/pump rigged to my ABG Intex pool (see signature for details) that has had nothing but FiberClear fed through it as a medium. I bought it brand new and it's been in service for three seasons, and it seems as though every season it has become progressively more difficult to keep at an optimum operating pressure and cleanliness. In the beginning, I charged the filter with 10 oz. of the FiberClear (1/8th the recommended weight of D.E. my filter normally is charged with, as per FC instructions) and the pressure settled in at 13-14 psi. It did a fantastic job that first summer staying clean and keeping the water clear.
After disassembling and cleaning it for the winter it went back into service the second season, this time with a Hayward NG heater in-line after the pump/filter. That's when I began to pay much more attention to the pressure, and how the filter becoming dirty would affect water flow, because low flow and my gas heater don't go well together. A the pressure crept up toward 18 and 20 psi, the heater would sometimes make a squealing noise, so I frequently was bumping it and even disassembling it once or twice in-season in order to keep the pressure down and the flow up.
And this summer has been even more of the same; frequent bumps and occasional disassembly and hosing down the tubes, which all seem fine and in good shape, but brown and dirty looking, even after hosing them off. Now, at the end of Season 3, I can barely get the pressure down to 16 or 17 at startup immediately after taking it apart and hosing it off.
My question for anyone using cellulose in a D.E. filter is, is there some process I need to go through this offseason to do a better job of cleaning the elements, in order that it will perform closer to that first season? What am I missing? Thanks.