I just noticed that the gauge on my 75 cubic foot Omega tank is leaking the glycerin out slowly. I can't tell exactly where it is coming from but it is slowly dripping. I don't think it has been bumped but who knows for sure as I let other shooters use it at our range. What happens if the gauge has no glycerin? I assume that if I change it I don't have to worry about draining the tank as it only shows pressure when the valve is open. Your thoughts please.