Lights on and off for chaeto to balance PH?

[Ippyroy]

I currently have my fuge light on for 8 hours and my DT for 12. During the first period with no lights, 3 hours, my PH drops quickly. Would it be ok to run the fuge light 1 hour on, 30minutes off? I am hoping this would cut down the PH swing, but how would that affect the chaeto?

 

[Spare time]

It wouldn't matter.