I have been having the same problem. I added DE (enough to raise my PSI 1) to try and clear the cloudiness. However, after adding I lost return pressure. I had to back wash to get the pressure back up ( I have had to do this three times since adding the DE). I am 2 weeks into a slam (pool was pond/green) I now have about 2 feet of visibility with no real change over the last week. I can't seem to meet all the SLAM criteria. I pass the over night FC test but still loose chlorine throughout the day. HELP what am I doing wrong?!?Yes, I watch the gage, it goes from 16 to 17 psi. I have been back washing at 20-21 psi, then put the DE in again. I'm sure it's just time, at least it's not green!