We have an in ground finite pool. Underground plumbing located approximately 40 feet away. Triton filter, 2" piping. Afternoons pump flow priesthood at full force and drops to about half flow after several hours and continues at 1/2 - 1/3 flow. Pressure seems higher than normal on the filter. The baskets are clean so nothin is clogging or blocking TH flow that w can see. SUGGESTIONS???