I have my motor just sitting in the tub and hanging there by its cord. It does have to be covered at all times by the cleaning fluid. If you're running water in the washer make sure that the motor is mounted in the layer where the cleaning fluid is and not in the water. Been running my system for 9 years and have never had a problem. All the sediment and gunk falls into the bottom and in no way comes in contact with the pump. Cleaned my tub about 3 years ago and took out about 2-3" of sludge.