The Aquascape Ultra™ Pump will provide years of trouble-free operation when properly maintained. If your Ultra™ Pump stops working try cleaning the protective input strainer and sponge. Another tip is to remove and clean the impeller and impeller housing with a mild acid-like white vinegar and toothbrush. This will remove any white scale build-up and allow the pump to run like new again. Note: replacement impeller kits are available.