Hi Guys,

Thanks for all the information.

I was wondering if, perhaps towards the end of the CO2 bottle, the CO2 concentration was to drop due to "normal air" starting to come out with the mix - requiring the needle valve to have to be set higher.

I get my bottle filled at a home brew shop and I was concerned one day when the guy there wasn't able to completely fill my bottle (because his shop bottle ran out).

I noticed that towards the end of the bottle, I had to crank my CO2 up to a ridiculously high level....and I was therefore wondering if perhaps the last part of my bottle was nothing more than "compressed air"....

Must of been some other factor at play that I overlooked.

So ok; not possible.