Could an ambient temp change cause it?? Is your wife posting on another board wondering why the bubble count seems to be going up every morning :biggrin:
My valve is so sensitive that I have to hold my breathe when I adjust it. Also difficult to get the bpm when its over 100.

Tony, (I really don't want to say this and don't know how phrase it better but ) have you tried tightening the two nuts behind the knob. Ya, laugh it up!

My first thought was ambient temperature too. But you'd think the rate would return to normal when the ambient temperature went back to normal? (Or go to a higher rate since the needle valve was opened a bit.) This doesn't happen. :confused:

Do you (should you) teflon any of your joins?

What's a good way to check for leaks? Soapy water?

Thats what I have always used. Lots of soap makes big bubbles with even the smallest leak. Thats still weird with the drop in pressure of co2 output over a 12hr period. Did you snug up the nuts or even mark the position of the knob to rule out valve turning?