best way to maintain PH with a reactor??

[untamed]

I've managed to get my pH to bounce daily between 8.15 and 8.0, even though my Alk is only about 8.

The two-stage Ca reactor runs only during the daylight cycle. Reactor is at pH 6.5, but exits the 2nd stage at more like 7.2.

The Kalk reactor runs only during the night. pH of supplied Kalk is about 12.5.

Refugium lit on opposite cycle to display tank.

BIG skimmer breathing in-house air.

I went after controlling pH in a big way some months back and this is the result. I don't think controlling pH fixed the problems I was having... but I suppose I'm better off for the effort.