I've seen some tanks dating back to 1920. Far and few but they are there. Easiest way to tell is the 4 digit code on top tank neck, typically split by asterix or line (XX*XX or XX|XX) the code means this: first two digits month and the second two digits year. Whatever one is latest is the last...
Hey there. tried to do the same thing, however gets tricky. I got a co2 splitter from these guys and they also provided the regulator and any fittings to adapt, seems like they've done it before. Sites geared towards effects but they definitely to know a plethora about co2 in general, including...