Warning! When you get our product for the first time, please calibrate the CO2 sensor first! Please make sure that the controller is working after the CO2 sensor warm-up 3 mins end.
Between growing cycles or at least once a year, you should manually re-calibrate the CO2 sensor. We recommend you use fresh air (~400 ppm) for calibrating by taking the controller outdoors, plugging it in, and following the procedure below.
Make sure the device is far from a source of CO2, not in direct sunlight, and not exposed to water. Step away from the unit during calibration.