pH increasing with lower alkalinity?

[Lago]

Hey I was wondering if anyone has an answer to this, but whenever my alk fell to ~8.5 dKH I ended up having a higher pH (8.1-8.2) for a day or 2 before my apex corrected the alk to 9. Whereas when the tank ran around 9 dKH, pH was running around 7.7-7.9. From the reading I've done the opposite should be true? To eliminate the possibility of the co2 media being all used up I changed out the scrubber media and there was no change in the pH values (in actuality it's dropping 7.84 pH and it's 11:14 AM). I can't think of any other reason as to why I am seeing this because no one else is in the room and I'm off at my college campus most days. So if anyone has a reason as to why I am seeing this it would be much appreciated. Thanks :)

Some general things before anyone asks:
-I've been dosing kalkwasser, running my refugium, and a recirculating co2 scrubber prior to the high pH increase.
-No other livestock has been added for the past month.
-Calcium stays around 430 and mag sits at 1400 also if that helps.

 

[Randy Holmes-Farley Verified Community Expert]

If the effect is other than random chance, I’d suggest the effect is the other way around: higher pH results in higher alk demand so the value for alk drops until the dosing is raised.

 

[Lago]

If the effect is other than random chance, I’d suggest the effect is the other way around: higher pH results in higher alk demand so the value for alk drops until the dosing is raised.

Yeah, that's the understanding I got from reading up on your previous posts. Along with working in a aquaculture lab on my college campus I see the same things that you describe. However, I just can't seem to pin a reason as for why I'm seeing this on my home tank. I also haven't had my windows open in a long while due to it being in the 90's as of late.