I have recently installed a CO2 system in my 75 gallon aquarium and it is
working fine except for one little problem. I have a constant pH reading of
7.1 thanks to the addition of CO2. Before CO2 my pH was 8.4. Very hard
water.

The problem is that when I fill my bubble counter half full of water, I lose
it all within a week. I believe the bubble flow rate is too fast and the
large flow is causing the water to dissipate into the CO2 air tubing. I
replace it and then is starts over again.

I know the answer is to turn down the flow rate, but then the CO2 runs all
the time on my pH controller. Isn't it supposed to shut off and then when
the pH spikes a little, it automatically turns it back on? I am afraid if I
turn down the flow rate, my pH will go higher than I want. The pH is
stabilized at 7.1 now so does it matter if there is water in the bubble
counter at this point anyhow?

Advice is appreciated from those with more experience and thanks.

Dan