Is a pond de-icer necessary in a backyard pond?
Many gardeners in colder climates are faced with the dilemma of weather or not they need a de-icer for their garden ponds.
A pond heater or de-icer is necessary if you have live in an area that is cold enough to completely freeze the surface of the water and you keep over winter fish in the pond.
Under normal conditions debris decomposing in a pond releases a gas that then dissipates into the air. If the surface freezes over and does not allow these toxic gasses to escape it can be deadly to the fish.
Therefore it is a necessity to keep a hole in the ice surface over the winter. Never allow the surface to freeze over and then try to open an area by banging a hole in it. Massive shock waves are sent through the water and ultimately will kill the fish.
A better way to vent these gases is to use a floating pond de-icer. A de-icer is a nearly indestructible heating unit that is safe for both fish and liners. The deicer will come with an internal temperature switch that will turn on only when the water hits below freezing and will turn off when water temperature rises to about 45 degrees. A common-size deicer is about 1250 Watts. It will maintain about an eight inch diameter hole in a 600 gallon pond. For larger ponds, a good rule-of-thumb is to add an additional unit for each 600 gallons of water. To obtain the best results from your deicer you should try to install it in a protected area away from high winds.
For small and shallow ponds, 12 - 24 inches deep I strongly suggest the use of a pond heater. A properly installed pond deicer can be the difference between life and death for your favorite Koi or goldfish.