I can give you my numbers for comparison if that's any help. Running 2" piping with a 2HP pump (Got suckered into the bigger is better prior to finding this place). Anyhow, it's a Waterway Crystal Water DE 60 Sqft. When completely broken down and cleaned and recharged, I get a PSI hovering around 18-22 depending on whether the Solar is "on". Even after curing a new plaster finish, my PSI reading never got higher than 26 (after 6 months). I tore it down knowing that there must have been a huge mess of plaster inside, and there was. Anyhow, I've gone 6 months without a backwash and the PSI never moves more than 3-4. It's definitely oversized for my pool (16k), so that may explain the long time between cleanings.