I'm a new pool owner slowly figuring all this out...thanks to this site!!
I have a cartridge filter: Hayward C12002. When we finally got the pump flowing, the psi was 8. So I figured, once it reaches about 10-11 psi is when I should clean it, right? (Normal pumping pressure + 20-25%). Today I saw it was at about 11 psi - time to clean the filter, right!? I open it up, take out the cartridge, do the hose spray method (wow...some "interesting" stuff came out of there), buttoned it all back up, and turned on the pump. My pressure immediately shot back up to 11 psi.
Is that the new/normal pressure (maybe the 8psi was just the startup/break in pressure)? Or do I need to clean it more/again?