is it a regulator with a solenoid on it? I have one of those for my planted aquarium. if that's the case, its fine. when power is applied to the solenoid, the valve is open.
you set these up on a timer or pH monitor that kills the power during lights out or if the pH drops too low....basically at times when you don't need extra CO2 for aquatic plants.
Primary: English Mild
On tap: Pale Ale, Lancelot's Wheat, English Brown Ale, Steam Beer, HoovNuts IPA
Bottled: MOAM, Braggot, Raspberry Melomel, Merlot, Apfelwein, Pyment, Sweet mead, Cabernet
Gal in 2009: 27, Gal in 2010: 34, Gal in 2011: 13, Gal in 2012: 10