Replacement Impellers for Complete Aquatics ProficientFlow™ Asynchronous Pumps Size:Fits 6500 Pump 3JF models include CF 3235 controller Strands are bonded together 3JF models include CF 3235 controller with timer reducing the time consuming maintenance of filling by hose and protecting the pump from running dry We strongly recommend cleaning out the well which houses the impeller with vinegar and an old toothbrush to eliminate mineral build up before installing the new impeller a frequent reason for problems is mineral build up way down inside the impeller housing which causes wear and tear on the impeller and friction against the impeller which can cause overheating and intermittent operation