So you already know that it is important to keep a hole open in the ice that forms over your water garden during the winter months. This provides an outlet for harmful gases and an inlet for new oxygen-rich air. The question now is which device do you choose to get the job done. The good news is if you have already made your purchase for the season either one will perform excellently. Both a heater and aerator will maintain a hole in the ice but unlike a pond heater, this is only one of many tasks an aeration system performs for your water garden.
When we talk about pond heaters we are referencing units like the Pondmaster Floating Pond De-Icer which does not heat the water in the pond but instead keeps a ring of water open allowing gas to escape through the vent in the top of the unit. Since most ponds deeper than 18” do not freeze solid this is all that is needed to allow oxygen exchange while the fish are dormant. When running a pond heater periodically check in on the pond to make sure ice does not form over the vent hole. To reduce electrical expense most pond heaters are thermostatically controlled to run only during a given temperature range, but they are measuring water temperature instead of air temperature. This means it is unlikely that the water temperature will raise enough to ever shut off the heater. To save some extra money on energy bills use a Thermo Cube in tandem with your pond heater as it will determine when your pond heater should run based on the ambient air temperature.
Aeration keeps a hole in the ice during the winter by producing bubbles and water motion to slow the ice from forming. This allows for the same gas exchange created by a pond heater, however your Aeration System will circulate the entire pond volume and infuse it with dissolved oxygen making it more efficient at oxygen/gas transfer. People will sometimes run pumps beneath the ice trying to create this same effect but it is the tiny air bubbles that boost dissolved oxygen levels and create the friction that prevents ice from forming. Your pond benefits from aeration year round making an aeration system a helpful and highly functional tool regardless of the season. The installation process is simple and straightforward and aeration systems are available in various sizes and shapes allowing you to select a system that best fits your pond. When selecting a system make sure you purchase a unit that is rated for your ponds volume in order to provide enough outlet for proper gas exchange.
The performance of both pond heaters and aeration systems vary depending on how cold it gets in your area. Even when vented properly, layers of ice appear may over when temperatures dip well below freezing. If this only occurs temporarily, and is short in duration while the coldest temperatures and wind are present, there should not be any cause for concern, as a calm or sunny day will give the pond the help it needs to re-open the hole in the ice. If it is necessary to manually reopen the air vent do not try to break through it by hitting it with hammers or heavy objects as this creates vibrations that can harm your fish. If necessary pour a bucket of warm water over the vent hole to melt it back open.
Whichever unit you choose to use will perform to keep your fish safe for the winter months and ensure that they will be healthy, happy and ready to go in the spring.
POND TALK: Which type of system have you found to work better in your pond? Do you still notice some ice formation?