Tetra's HT40 heater is easy-to-use and works in aquariums ranging from 30 to 40 gallons. The heater has an electronic thermostat that automatically adjusts tje heat output to keep the water at a constant 78 degrees F.
All Tetra HT heaters have red/green indicator lights to let you know when the heater is heating(red) or on standby(green). The low voltage thermostat maintains water at 78°F without any adjustment required. Be sure purchase the correct heater for your tank size. Buying a heater too small for your tank can cause under heating. It is critical to ensure your tank is equipped with a hood or glass canopy to contain the heat inside the aquarium. All Tetra HT Heaters will shut off if an electrical short is detected for your safety.