Strange semi-regular ph drops

[OscarHaglund]

Hi i am having a strange behaviour from my apex ph probe. Since a few weeks back every few days at 7 am the ph drops dramatically (up to 1.5 units) and then recovers within an hour. This kind of drop is clearly not realistic so there must be some kind of measurement error or interference.

Anyone got any ideas what it could be? I have not made any equipment changes since well before this started

 

[Randy Holmes-Farley]

Anything electric on a timer nearby? Or something you turn on or off every morning?

 

[OscarHaglund]

Anything electric on a timer nearby? Or something you turn on or off every morning?

Skimmer turns off on a timer around then and the lights turn on. But they are pretty far away. My apex is on the opposite side of the sump. Also does not explain why this doesn’t happen every day.

 

[Dan_P]

Skimmer turns off on a timer around then and the lights turn on. But they are pretty far away. My apex is on the opposite side of the sump. Also does not explain why this doesn’t happen every day.

Try leaving the skimmer on 24/7 for a week or two.

 

[Randy Holmes-Farley]

Check the timing carefully for the start of the downward spike and what happens exactly then, within seconds. Maybe watch the pH and tank in real time.

 

[Reefer Matt]

Is anything getting dosed into the tank that can lower the ph? Are you using anything to maintain ph, like a co2 reactor?