Could the CO2 bottle be near a heating duct? or near a drafty window? maybe
air movement thru the room is cooling/warming up the canister/regulator, and
somehow while it's condensing/expanding it's allowing the flow to change?

off the top of my head....


"Bill Beam" wrote in message
...
I've got a CO2 Tank/Reg system. I keep the out going pressure at
5psig into a needle valve. I have the valve set for 2 bubbles per
minute and it stays like that all day. Problem is - when I get up in
the morning the bubble rate is very slow - less than one bubble per
second. Pressure is the same. Resetting the rate with needle valve
works fine. Why would this be happening? This is one of those $25
needle valves from Foster/Smith. Should'nt it stay adjusted? Thanks
for the help.