70/30 mix regulator help

[soupdragon]

Hi all

When I got my corny's from Norm the other year I got a mix gas reg along with a co2 reg. I'd been given a bottle of mixed gas by someone who used to run a mobile bar so thought I'd make use of it. I've only now got around to brewing a mild and have set the mix gas up for it.
Got a question about the dial on the reg though.
Should the gauge be reading in the green bit when full? I'm presuming that as mine is showing slightly off the green bit that the bottle isn't full? How are this type of gauge calibrated? There's no half or quarter mark just a red line near empty.
Thanks in advance..........

Cheers Tom

[rpt]

As long as there is liquid in the bottle the pressure won't change much. Once all the liquid has evaporated and it is just gas, the pressure will drop fairly rapidly. At this point you know the bottle will be empty soon. This is why the gauge cannot be marked half full etc.

The bottle should have a tare weight stamped on it. Weigh the bottle and you can work out how much gas is left in it.

[soupdragon]

Thanks for the info. I'll have a look.

Cheers Tom