I have an 18' above ground pool and the pump that came with it just didn't circulate the watervery well. It started OK . Then it started moving the water slower and slower,until it would be on,but didin't move the water at all. It stopped working completely as if the motor had burned up, within a couple of months of buying the pool. I have been through at least 3 maybe 4 more of very same pump that is included in your pool pit kit. It just seem that these pumps are powerful enough or that the motor isn't strong enough to push the water like it should and I have to turn it off several hours so it might not burn up as fast as the other pumps running before the latest pumpin use. The pumps I have been using are a Krystal clear filter pump-model 637. It is 110-120 v,60 Hz,0.8 A

I don't deal in or work on above ground pools, but a pump is a pump. Other than for minor impeller wear, a pump usually pumps the same amount of water over the entire lifespan of the pump. The most common problem for reduced flow from a pump is a dirty filter, or in some cases a plugged impeller or plugged suction line. Replacing the pump would take care of the plugged impeller problem, but would still not pump much water if the filter was dirty and the resistance to flow was high. I would need to know what kind of filter you have, what the horsepower of your pump is, etc. and I might be able to give you some simple tests to do to isolate the problem. All pumps are rated by Gallons Per Minute based on resistance to flow. This number usually doesn't vary much no matter how old the pump is unless something else is changing.