Be careful out there. I picked up a new acetelyne tank yesterday. After hooking up, I checked for leaks at all the fittings. All was well, except..... After I shut of the tank valve, I watched the gage pressure slowly drop. Looks like a regulator diaphragm went out. This would have resulted in a slow leak any time the main valve was open. A three car garage full of acetelyne would make a helluva explosion.