John H. wrote:

I have a basic CO2 setup, 5 lb bottle with regulator. I filled it a 3-4
months ago and its almost empty?
I'm checking for leaks around the seals but how many bubbles per minute is
adaquate for plants. If I dont find any leaks then maybe I just had the flow
too high? (65gal tank)

I worked out that 2 bubbles per second will keep my tank at about 7.2 pH
from a natural 8.1 in a 75 UK gallon tank. At night, that's a different
rate, but my pH controller sorts that out by usually switching off the
CO2. It sounds like you may have a leak. But what pH drop are you
obtaining from your bubble rate.

Nikki