Make up a mixture of diluted washing liquid and use a spray bottle to spray around all the threads, fittings and anywhere there could be a leak. It sounds like it would be a pretty substantial leak, so it shouldn't be hard spotting bubbles expanding.Yeah, thanks! I still think there's something else going on with this CO2 setup, it seemed fine, but I've already run out of CO2, in less than a month. Considering the last fill-up lasted about 4 months, something is still wrong. Gotta have a leak somewhere, just gotta find it... In the meantime, I've got no CO2.