I have a cartridge filter for an above ground pool that doesn't seem to be filtering. When I vacuum, any dirt, debris, or algae flows right back into the pool.
I've checked the cartridge, there are no tears or holes. I've tried a different cartridge.
The only thing that seems out of the ordinary is that at the bottom of the cartridge housing, there's a little floaty thing in the return pipe that the cartridge surrounds. The floaty has a flat side and a rounded side. I don't know which should be facing up. Doesn't seem to matter, though, as I've tried both.
When I leave the filter running over night, in the morning if I take the cap off the cartridge housing, it's only about 20% full of water.
The pressure gauge isn't abnormal.
I was able to fix this once by closing a valve to the pool for a split second to make the pressure spike. I don't know if that knocked something loose or what, but it seems to have only been a one time fix.
Any help would be greatly appreciated!