Normal PSI filter ?

[xoroniox]

Hey,
ok so here is my question i have a IG 28x14 pool , hayward 1hp maxiflo pump 1 month old with a 50sq hayward cartridge filter also 1month old with the psi gauge on the bottom of it, Is there a general "normal" psi reading for this setup? when i had my old cartridge in there normal was 10psi and when it needed cleaning it was around 15psi and since last month with the new cartridge just after i clean it, the reading is 15psi for about 10minutes and it jumps to 20psi. now i cant really see this meaning the water is so dirty that after 10minutes the cartridge needs to be cleaned again? or maybe its priming and 20psi is normal? since i put the cartridge in i have been cleaning it once a week and it has been reading 20psi each time. Also how often is normal to clean the cartridge or does it not matter since i am only washing it out with the hose/water? appreciate all the help!