Hydrofarm Custom Automated Products, CACGC1, Complete Greenhouse Controller (w/ppm Option) Complete Greenhouse Controller controls all of the main devices required in today's modern hydroponic gardenyour HID lights, supplemental CO2, hydroponic pumps, and exhaust fans or air conditioner. Other functions such as supplemental CO2 and hydroponic pumps are also coordinated with the time clock with a built-in thermostat and humistat handle the growing area's temperature and humidity control functions Your garden's HID lights are controlled by a precision 24-hour time clock. Two outlets are provided for your lights.