The Dennerle CO2 solenoid valve enables automatic control of the CO2 supply in either of two ways, thereby saving valuable CO2:A With a time switch: The time switch cuts off the supply of CO2 overnight, as aquarium plants do not require any CO2 during the night. TIP: Simply connect the CO2 solenoid valve to the time switch which controls your aquarium lighting.B With a Dennerle pH controller or aquarium computer: This controller continuously measures the pH value in the aquarium and controls the required supply of CO2 automatically with electronic precision.technical Data Dennerle CO2 Solenoid Valve:+ 230 V/50 Hz+ Power consumption: 1.6 W+ max. permissible perating pressure: 5 bar+ splash-proof+ connectors for hose 4/6 mm+ cable with Euro-Plug, length: 1.80 m