In my case, it stayed around 7.0 during the day, and just before the lights and C02 came back on it had risen to around 8.0. :shock: That's with a KH of around 9. Now with the controller, it hangs at 7.0 and I'm sure my poor fish appreciate it much more. Maybe my Hongsloi's will reward me with a spawning now.... :wink:Allthingsaquatic said:I thought i would just add. Out of curiosity, with the unit on or off at night, how much of a ph fluctuation do you guys see. Im not currently using a co2 setup, i have in the past but scrapped it. Is it a full 1.0, or are we talking 10ths of a ph here? Just your own findings, thanks.