Free Shipping. Pondmaster 120 Watt De-icer has 120 watts of heating power, thermostatic control, double watertight seal, and will not harm flexible or preformed pools. Colored red so that you can easily locate the de-icer in your pond. In areas where the threat of ice in winter is obvious, the necessity of a pool heater should be considered. The aquatic life in your pond, especially the fish, cannot survive heavy ice buildup and noxious gases may be trapped. An automatic thermostat senses the water temperature and turns on when the temperature of the water approaches freezing. Has a 18 foot power cord. Does not harm pond liners or plastic ponds and does not need a pond guard. One unit per 2000 gallons. This unit has a protected heating element that does not need to be routine cleaned with lime removing cleaners.