If you have an outdoor pond, it is very important to create a healthy living environment year-round, especially if the pond contains fish and live plants, and a fish pond heater can help you do just that. There are two basic types of fish pond heaters—submersible heaters and heaters that float along the surface. Learn more about how each functions before you make the choice of which to buy.
Submersible Fish Pond Heaters
Submersible heaters rest on the bottom of the pond and heat a general area, allowing the fish to swim freely in warmer waters. In most cases, the heater is controlled by a thermostat controller that gets plugged into a nearby GFCI-protected outlet.
The controller has a temperature probe that signals when it's time to turn the heater on and off. Advanced models have floats that keep tabs on how high or low the water level is getting, which can directly impact the need for increased or reduced heat.
Floating Fish Pond Heaters
In order for your fish to stay healthy all year around, it’s important that oxygen be able to enter the pond and toxic gases be able to leave. Neither of these processes is possible whenever the surface of the pond is frozen over with a layer of ice. A floating fish pond heater rests on the surface of the water and turns on whenever the air temperature dips to a certain degree. While some of the pond may freeze, the floating heater ensures that a portion of it doesn’t so the fish get the oxygen they need.
Maximizing the Effectiveness of Your Submersible Heater
When choosing a submersible pond heater, the general rule of thumb is one watt per gallon of water equals a ten degree increase over a 24-hour period. So, if you have a 500 gallon pond filled with 50 degree water and you’re heating it with a 1,000 watt submersible heater, the temperature of the water will rise to 70 degrees over a 24 hour period.
Placing a piece of plywood over part of the pond will help keep the pond water warm. While this helps the heater work more efficiently in very cold climates, it is important not to cover the entire pond as gases need a way to escape.
If you have a waterfall or fountain, make sure they are turned off before the weather turns cold. These accessories actually work against the action of the heater and will cause the water to remain cold if they are left running.
A submersible heater’s thermostat controller unit must be kept out of the elements or it will be damaged. Many supply stores sell plastic containers for this purpose or a Rubbermaid container will also do the trick.
Maximizing the Effectiveness of Your Floating Heater
To get the most out of your floating pond heater, it’s best to position it near part of the pool liner in a shallow part of the pond. The liner will reflect the heat from the heater back into the water for a broader layer of warmth.
Use one floating pond de-icer or heater for a 600-gallon pond. If the pond is larger than 600 gallons, use two floating heaters.
Try to keep your floating heater protected from the wind. A strong, cold breeze can reduce the heater’s ability tremendously. Placing plywood over the pond will help in this instance as well.
It is not recommended to use extension cords to power your pond heater as the length of the cords will reduce the heating capacity of the heaters and make them incapable of maintaining a reliable temperature. A GFCI-protected outlet should be installed near the pond for the best results.
Every pond has different needs depending on size and local climate, as well as the fish and plants you've chosen to keep in it. Choosing the right type of heater is crucial, but you should also make sure you thoroughly research care instructions for the plants and fish you before buying them. This way, the heater purchase can keep the right environment and allow your plants and fish to thrive.
Dave Donovan is a freelance copywriter living in Atco, N.J. An electrician for 15 years, an injury forced him to pursue his true passion—writing.