Abstract: To provide an inexpensive, portable, and easy to use apparatus for applying a detergent to a used hot tub or other filter, a tank is provided with a submersible pump and has a large perforated tube affixed to its bottom. The filter to be cleaned is placed over this large tube. A readily disconnectable arrangement of tubing terminates in a small perforated tube at a first end and is connected to the outlet of the submersible pump at a second end. The large perforated tube is provided with a collar to keep the filter from floating and to prevent undesirable current flows around rather than through the filter. The small perforated tube fits within the large perforated tube after the filter and collar are in place.