I wonder about the PH drop also. When I turn the CO2 off at night my PH will rise from 6.7 to 7.4 by the time the CO2 is turned back on and the PH drops back to 6.7. I am not trying to target a specific PH, but I thought the idea was to avoid PH swings. I do have an airstone that turns on when the lights go out to ensure there is adequate oxygen at night.
Are the nightly PH swings a "don't care"?? Turning the CO2 off at night would be nice since the only thing it does during that time is maintain the PH level.
Thanks for any opinions!
What are your respective KH, and GH levels ? at dkh 5, and dgh 6 running air in my tickle filter at night my ph rises to 7.4 in the morning, and will return to 6.7 as well, once the Co2 and lighting resumes and eventually flatlines at ph 6.6 until nightfall. Without air it will rise to PH 7.1
I haven't noticed the fish stressing any, but the plants and livestock both DO seem to enjoy the additional air at night. I'd rather the swing was lower, but just haven't observed any adverse affect so long as the KH and GH are stable. Maintaining the PH is all well and good, but plants are every bit as greedy for o2 at night and I suspect it drives or fascilitates nutrient uptake.
Oddly enough on the organic system utilizing a yeast reactor I located the bottles adjacent to the massive Hamilton ballast under the stand, so once the lights go out Co2 production drops by half effectively accomplishing the same thing. Weird, but effective...HTH. Prof M