PH question

[SWherrey]

Im a bit confused… my understanding is Ph rises during the day and is supposed to drop at night.
I just purchased an Apex, set up and calibrated the probes. So what I am noticing is my Ph is dropping during the day to about 7.91 and towards the end of my light cycle my Ph starts to go up to about 8.16. I do have a refugium with chaeto and it is on reverse light cycle. Am I missing something here?

 

[Pico bam]

Idk maybe that chaeto is really throwing out some oxygen. Dosing anything when the lights are off? Certain things will make the ph higher.

 

[SWherrey]

Just ATI Essentials Pro is all I dose.

 

[ColoredRock]

Possible usage from the day (humans, pets) diminishing at night when the air breathers leave the room.

 

[SWherrey]

Nvm dumb me -.- rookie mistake….. so when my light cycle starts my Ph is about 7.91 and slowly rises topping out at 8.16 (at night) when my main light cycle ends before starting to drop again overnight…. Sorry! Haha