instructions:1. Before the product is powered on, check whether the heating rod is fixed in the fish tank and use it within the specified voltage range, otherwise the product will be damaged.2. Temperature calibration: after power on, the display will flash three times and then display the factory set temperature (20 °)3. Temperature regulation: after power on, press the temperature adjustment button on the side of the temperature controller by hand. The thermometer will change by one degree (17-32 ° cycle setting) every time you press it. Adjust the required target temperature and stop automatic temperature saving for three seconds.4. Please refer to the installation diagram for specific installation.