Fine Tuning a Salt Water Pool

[BigTallGuy]

I am very curious to hear any new "Best Guess" data. Please keep me in the loop. I have learned that FC readings of 5.0 are reasonably good for a Salt water pool, so I am reasonably comfortable with these numbers.

This question has been rolling around in the back of my mind for sometime now. Is there any information on the Chlorine curve in a normal day? Here is what I mean and I can already guess that a lot will depend upon the CYA, the amount of sunlight, and other factors.

If I check the FC at daybreak with my old cheap plastic tester (no pool stores are open at daybreak and I can't test in the dark) I would get a reading of 5.0 as an example. Then if I re-test FC again at sundown, I would think I should see a significant loss say down to 3.0 or something. Now these are not actual readings they're just examples.

When I test in the late afternoon when I get home from work, my actual Chlorine readings are 5.0ish, so would this tend to indicate that I am starting out at something like 10.0 in the morning, or is the normal curve much flatter than that?

BTW, my old cheap plastic tester only goes to 3.0 on the FC scale and says 1.0 - 1.5 FC is "Ideal". I know I need a new tester, and trying to get meaningful readings that are actually "off the chart" with my old one is difficult at best. Again my thought is, I am comparing apples to oranges with a Salt vs. Traditional Chlorine systems.

As always all comments are welcome and appreciated. BTDG