AQQA Aquarium Heater, 300W/500W/800W Submersible Fish Tank Heater with PTC Rapid Heating, Precise Digital Temperature Controller, LED Display with Memory Function for Up to 250 Gallon Freshwater Tank

About this item Rapid and Safe Heating: The aquarium heater is made of PTC new ceramic semiconductor material and covered with graphene coating that heats the water quickly and safely, and more energy-efficient. Precise Temperature Control System: The large LED display shows the set temperature with one decimal place and the temperature control is accurate to 0.5℉. You can set the temperature safely and conveniently using the controller. The adjustable temperature range of fish tank heater is 59℉-94℉. Constant Temperature Inverter Technology: If the difference between the actual water temperature and the set temperature is less than 0.5°F, the aquarium heater will heat at a lower power. If the difference between the actual water temperature and the set water temperature is more than 0.6°F, the heater heats at high power, keeping the water temperature constant quickly and accurately and reducing the water temperature difference. 2 Automatic Power-off Protection Function: If more than 2 inches of the heater is above the water surface, it stops heating and the overheating protection is automatically activated, and the indicator light flashes to indicate a lack of water. The error message “Er” appears on the display. If the water temperature exceeds 95℉, the indicator light iluminates as an overtemperature alarm, and the error message “EE”is displayed. Memory Function & Simple Operation: When the power is restored after a power shutdown, the previous settings will be retained. Press and hold the setting button for 3 seconds to unlock the controller. Press the up and down buttons to adjust the set temperature. If the controller is not operated for 3 seconds. it automatically switches to childproof mode, ensuring the safety of children and fish.