Simple CO2 Solenoid Carbon Doser Project

Controlling pressurized carbon dioxide (CO2) delivery into a Calcium reactor or into a planted tank with precision can be fraught with problems. The conventional mechanism is to use a needle valve after a pressure regulator - this design is very finicky to adjust for low flow rates and has a tendency to drift over time, meaning your carefully controlled delivery is now out of whack. In addition, if you use a pH controller driving an AC solenoid valve, the valve actuation can be quite audible.