It is convenient to have a submersible pump available for lowering the pool water level.
In draining pool water there is always the risk of forgetting and getting the water too low and the pump running dry. Using your pool pump risks an expensive pump. You would rather accidentally damage an inexpensive submersible pump then and expensive pool pump.
There are many submersible pumps available at hardware stores and online. The pumps do not pump anywhere near their claimed GPM through a garden hose. If you use a regular garden hose that is ~50' long you will most likely get less than 10 gpm output. Around 1/2 HP Utility pump works fine with a garden hose.
Usually you want a "utility pump" and not a "sump pump".
Pumps mentioned by members include:
- Flotec FP0S1300X-03 Tempest Fpos1300X Multi-Purpose Water Removal Utility Pump
- Superior Pump 91330 1/3 HP Thermoplastic Submersible Utility Pump
- Drummond 1/3 HP Submersible Utility Pump[1]
Leaving a submersible pump in the pool can create rust stains.[2] Cheap submersible pumps are not designed for continuous submerged applications. They are design as point of use water removal devices. The cheap ones often have externally exposed metal screens that are not high quality stainless steel. These pumps are not designed for moving water over long periods of time and pool water can easily become corrosive towards metals when chlorine and chloride are present.