How to adjust the Aquarium Co-Op heater
To adjust the heater to the desired temperature, press the SET button once on the temperature controller. While the temperature display is still blinking, press the SET button again to change the desired temperature by 1°F increments. (The desired temperature cycles from 64°F to 91°F, meaning that you need to increase the heater up to the highest temperature setting of 91°F before it goes back down to 64°F.) When the desired temperature is reached, do not touch the SET button for 3 seconds. Once the blinking stops, the desired temperature has been saved.
For more information, see the heater product page.