I just bought a house with an above ground pool. About 16ft. It hasn't been open in a couple years. I bought a new pump and new sand. I cleaned out the filter. Added half water. Added a little sand. Placed the thing in there with the arms that fold down, then 3 maybe 4 bags of sand. Backwashed for two minutes and then rinsed for 1 minute. Pump seems to work fine, but it loses pressure within about a half hour. The jet has great pressure then starts to die out. I just found out that this is wrong BUT what I would do to get the pressure back is to backwash it again until the seeing glass on the side was clear water again then I would run filter normal again. Same thing happens. About 15-30 minutes its dead again. Not much water coming out. Now I thought maybe it was just because the water is so dirty and this was normal but I found out that is not the case and I should not have to backwash every 15 minutes. Do I have too much sand in there? Not enough sand? Why is the pressure so bad after a while? I tried hooking my vacuum hose up also to clean the bottom. Now its very dirty down there. But after a few passes, I see brown water shoot out of the jet. So of course I backwash again. What should I do here?