At what point to you replace the water? What specific gravity? I have found that as the bubbler water reaches a certain amount of KOH, it becomes very foamy and will fell the top portion of the bubbler with foam, even forcing it into the supply line. And this happens a lot sooner than I'd like for it to. I have a cell on my bench that I'd doing a destructive test on, and I'm running it pretty hard and it's making a lot of vapor (no steam, though). Production is about 3 lpm AFTER bubbler. But I need to change the bubbler water almost every other day (running it 8-9 hours a day) to keep the foam down. If I add 50% vinegar I get another 8 hours before having to change.
1991 Plymouth Acclaim 3L V6.
1 dry cells with nineteen 6"x8" 316L ss plates, driven by constant current PWM set at 35 amps (13.3V at PWM). 28% KOH electrolyte. Total measured output 2.5 lpm. Mileage went from 18 to 26 mpg, all city driving (44% increase). EFIE set at .370 and I still need to play with ignition timing.