Heat Exchangers are the most cost effective method of controlling the water temperature of Ponds. Using a Heat Exchanger provides a method of heating water by simply pumping the water, on it's return to the pond in much the same you would connect a UV sterilizer.
Water enters through the Inlet Pipe and then circulates past an inner Stainless Steel Coil. The coil contains hot water from the boiler. The heat from the 'Hot Water' in the inner coil never makes contact with the actual pond water but the heat generated from it is then transferred to the water flowing round it by radiation providing heat to your pond.
1 1/2" Male threaded fitting for pond water, 3/4" male for heating circuit.