The Colombo CO2 Solenoid should be used with a domestic timer (just like your lights timer) and automates when your CO2 comes on and off. We recommend it comes on 1 hour before your lights come on and turn off 1 hour before they go off (this is optimal).
By using this solenoid you will not only save a lot of gas, reduce any risk to your fish/shrimp and save you plenty of money (as you won't need to purchase CO2 bottles as often)