My aquarium heater is not working properly, what can I do?

If your heater is not maintaining the correct temperature, make sure it has been in operation for 36 hours. The heater will slowly raise or lower the temperature over time. This will prevent a large temperature swing that can shock the fish. If it is still not working properly, please contact Tetra. Please note: never remove a heater from the water if it is still turned on. Unplug it first, let it cool, and then remove it.