We have a 10K gallon, unground pool that was installed 5 years ago. The 1st year was great and then the next 3 we had pressure issues. We had a 1 cartridge pump and after cleaning a new filter the first time the pressure would jump to 15-20 in a few hours reducing and sometimes stopping the output of water back into the pool.
We had a "pool guy" come out a few weeks ago and he said our pump was too small for our size pool. We bought a much larger pump (4 cartridges) and started running it. Our pool was very dirty and by the next day the pool was crystal clear and we had to clean the cartridges. We clean with a garden hose with some pressure but not enough to loosen the cartridge from the bands. We've cleaned these filters 3-4 times in a 3 week period and only used the pool once so we didn't track too much dirt/grass into the water. We also use an electric pool cleaner which cleans a lot of the dirt.
So now with a bigger and new pump, clean cartridges and not a large use of the pool we cannot keep the pressure below 12-15. As soon as the pump is turned on the pressure goes to 5 right away and then creeps higher. The company who installed the new pump has already said he doesn't know why the pressure is not staying low after cleaning and is not returning our calls.
I read a thread stating possibly someone's pool still had a lot of dead (particles/algae???) even though the water is clear. Does anyone have any suggestions on what could be going on. Should we keep cleaning the filters and this should clear itself up?