My normal Psi is 11 all day long.
Yesterday I cleaned my solar cover brushing everything in to the skimmer. I use skimmer socks religiously so I changed it out after the solar cover cleaning it was full with pollen. I pulled the cover off after cleaning and cleaned my pool for the week with my normal routine. I went to a party and when I got home my Psi had shot up to 21. I turned off the pump since it was almost dark. This morning before work I backwashed twice since I couldn't get the pressure below 15, the waste was really yellow with pollen. I ran it for a couple of hours and it stayed at 15. I turned off the pump and figured I would deal with it when I got home from work. I came home and turned on the pump and the pressure is now 14. I can't figure out why my pressure is all over the board and won't drop back to 11. My gauge says 0 when the pump is off and I replaced it last August with one of the ones Dave sells from this site.
I checked my skimmer sock, main drain to make sure nothing is clogging it, cleaned the pump basket and checked my returns the pressure is fine. I really backwashed it the second time thinking the filter was still dirty. Everything looks/sounds normal except the pressure.
I had my sand replaced over the winter and a new multiport put on a couple of weeks ago could any of this be the reason behind the pressure change? any ideas?