"Andy" wrote in message ...
Greetings,
I'm planning a homemade CO2 system - I'm after a well regulated bubble rate.
At first I thought maybe I'd put a pressure regulator with just the 2 liter
pop bottle setup, but I assume backpressure could make the bottle explode.

Don't worry too much about back-pressure exploding the bottle. In
middle school I was made a pressurized water gun - a 2L bottle with
the valve stem of an old inner tube. It held pressure to 80 psi
without exploding, but I usually kept it back down at less than 40
psi.