First post! A few testing questions...

[Henrys514]

It was helpful, thank you! Couple more questions...

Is the evening the best time for testing and adding chemicals?

If I'm only testing TC, I guess it's hard to know when I need to shock the pool since I won't know the CC value? Pool store tests for FC only, but their test only goes up to 5ppm, and they never dilute...they just report 5 . I might have to get me one of the DPD or FAS-DPD tests.

That's what I thought about the CYA/Chlorine interaction...if you have a higher CYA, you can get away with a higher Chlorine because you need it.

[waterbear]

best time for testing is when you can do it at pretty much the same time each time.
Ditto for adding chems.
Evening is good but you really need to do the tests under natural light but not direct sun.