Actually that may be more harmful, because as soon as the air pump turns on, the co2 will be driven off quickly....which means pH will plummet up. Thats not very healthy for your fish.
The best way to determine if everything is ok, is like I said, test it yourself. Stay up until 2, taking readings every hour or two hours. If notice a radical drop, thats a problem. But you shouldn't.
I haven't made my reactor yet, so I have a ladder, and whatever doesn't dissolve there goes into a powerhead which breaks it up into small bubbles. The power head turns off at night for me, and I have never added any air (my levels are perfectly fine). Some people do what you're planning, but most people dont, and there isn't a problem.