My PH ranges from 7.1 early AM to 6.8/6.9 when the lights go off. My KH is
4 degrees. Looking up the chart, if I read it correctly, I'm at or near
ideal CO2 levels.
Yes, that's pretty good. Though it would be better if you could keep it at 6.8
all the time.
I've only just started to use tap water. It was RO before that. I'm now
mixing about 50/50 RO to tap on changes.
That might help. Straight RO water isn't ideal for plants.
Leigh
http://www.fortunecity.com/lavender/halloween/881/