I completly agree, stable ph is way better, I add a small bit of coral to keep my ph that comes from the tap, which is a solid 7 from fluctuating too much. I wasn't sure how much a ph can fall due to co2, but mine fell quite low, and killed off the majority of my fish, and the few plants i had thrown in there.
to wkndracer: i have no clue what kind of heater they installed, I know they put backup electric heaters in, but I'm not sure what the main heater is
to overstocked: so co2 induced ph swings wont hurt my fish? I was a little worried about that, if i added an airstone at night, do you think i would have to remove the co2 at night, or would my fish be ok?