If by stable you mean the same reading 24/7
I guess I don't mean stable within a day/night cycle, but stable over weeks or months
. But you bring up a good point, maybe CO2 should actually be "allowed" to fluctuate during the day/night, maybe that's "better" than holding a constant ppm.
Where I am going is that it's tricky to dial in the right amount of CO2 (bpm), and once that's done, how often do we need to re-check the system
? Maybe you have things configured such that the drop checker is green (30ppm), but then you do some trimming (removed plant mass) and the next day, the drop checker is yellow and you've gassed fish. Or the opposite, the water level evaporates to below the filter outlet and suddenly more CO2 is being off-gassed...leading to algae!
what happens to that PPM when you do a 25 or 50% water change?
I imagine that within a few hours it's back to where it was, but really I don't know! I haven't heard of this being an issue.
I've measured actual CO2 levels in a low tech dirt tank.
Thanks! Interesting to see the drop during the day and immediate rise after lights-off. Any chance you've taken measurements spread out over several days or weeks?