What is Co2 Regulator ?

Co2 regulators are what control (or regulate) the flow of CO2 to your aquarium. I suggest using one with an electronic solenoid that can be set on a timer so you can control when it goes on and off automatically. Since plants only consume CO2 during photosynthesis (when light is available), it is a waste of gas to run Co2 when your lights are off.  Plus if you run your CO2 overnight, it can build up in the tank and kill your fish or at the very least cause unstable levels of CO2 as it accumulates at night and drains during the day. Most regulators these days have a needle valve built into them so you can control the flow (of how much gas is going into the tank). Lastly, they all have gauges that show you how much pressure is in your reserve tank, and the regulator from Uuidear can also show the amount of pressure in your Co2 system.