Easy-to-use submersible heaters automatically maintain aquarium water temperature at 78°F (±2°). Tetra HT Submersible Aquarium Heaters feature an electronic thermostat that adjusts heat output to maintain constant water temperature. Preset heater technology reduces the risk of overheating and prolongs the life of the heater. Indicator light allows simple visual confirmation of heater operation. Units display a red light when the water is heating and a green light when water is at the proper temperature.

Tetra HT Submersible Aquarium Heaters are made of heat and shock resistant borosilicate glass. 6 foot cord. UL-Listed.

Useful Recommendations:

1. If the heater needs to be removed from the aquarium, unplug the power cord and wait 15 minutes to allow heater to cool before removing it.
2. Note: This heater is for indoor aquarium use only.
3. It is a good idea to use a light hood or glass cover to prevent excessive heat loss from any aquarium. Using a hood or cover with aquariums over 10 gallons will provide the best conditions for heating the aquarium.

Instructions:

1. The heater can be placed either vertically or horizontally in the aquarium. Placing the heater horizontally near the bottom of the aquarium eliminates the need to remove it during normal water changes (25-50% of water). Always unplug the heater 15 minutes prior to exposing it to air. Note: The heater should always be completely submerged in water when plugged into an electric receptacle.
2. Attach suction cup by pressing firmly onto the aquarium wall. For best results, the aquarium wall should be free from algae. Place the heater in an area with good water circulation.
3. Arrange a "drip loop" to prevent water from traveling along the cord and coming into contact with the receptacle. The "drip loop" is that part of the cord below the level of the receptacle or the connector, if an extension cord is used, to prevent water traveling along the cord and coming in contact with the receptacle. Note: If the plug or receptacle does get wet, don't unplug the cord. Disconnect the fuse or circuit breaker that supplies power to the appliance. Then unplug and examine for presence of water in the receptacle.
4. (DO NOT OPERATE THE HEATER DRY; it must be placed in a water-filled aquarium before plugging the power cord into a power outlet.) Once the aquarium is filled with water, wait 15 minutes, then plug heater into electric receptacle. When the unit is heating, a red indicator light will glow. The light will change to green when the optimum temperature has been reached.
5. The most common temperature for fish is 78°F. Your Submersible Heater automatically adjusts to maintain the proper temperature for your fish (78° to 80°F). In a newly setup aquarium, allow 24 hours for the water to reach the correct temperature before adding fish.