I built a kegerator out of a chest freezer that has 4 taps. I currently have 3 beers on tap and I have been going through CO2 like crazy. Should I be shutting off the valves when not in use? I have, at best between me and my wife, 3 beers a night but I leave the gas on all the time. Is it normal to go through a 10lb CO2 tank in a couple of days?