I'm at a loss with my de filter. Pre coat pressure starts at 11 psi. It works well with a strong flow for approx 3 hrs. Pressure climbs up, bump the handle, I've done this since 3pm yesterday (5/19) and several days prior. I've done complete cleanouts, I've been thru 20 lbs of de with minimal results to the water.

I've disassembled the filter, installed a different rubber diaphram, lubricated it along with all o-rings, including pump basket oring. Soaked the fingers in muriatic acid wash and tsp soak. No apparent suction leak, pump basket is solid with water. Now I'm stuck.  Anyone have any other ideas?

Thank you