Time of day to add chemicals

So long as you feed your pool chlorine before it gets to minimum for your cya
FC/CYA Levels the time of day/night doesn’t matter.
You can add cya or ma any time you wish so long as you wait a few minutes between each chemical/don’t mix them.

It is really about consistency with a manually dosed chlorine pool. Test your pool before your daily additions. This will yield a pattern that gives you insight on your pool. Before I got a SWG, I added chlorine every evening after testing. To ensure what I added the day before was still above minimum. Really, my mimimum was the lower range of my target and dosed to above the upper range. For example, with CYA 50 the target range was FC 6 - 8. I dosed to 10 then when I checked the next day I may have been at 7 or 6 if it was a high UV day. The minimum was 4. I never wanted to be near the minimum.