Yep, You should always have Free Chlorine in your pool. When I say residual, I meant still some left after it's been used by sun and swimmers.

You are on the Best Guess Chart (good) in the morning when you test. I highly suspect that the sun depletes all your chlorine pretty quickly however.

I'm asking you to test several times a day because you are in start-up mode, with very little CYA in the water and we want to you maintain FC to keep the pool sanitary and clear. Once we know that we're holding FC throughout the day, we can back off to daily testing.

If it's not possible to test several times a day, then I'll ask you to use larger and larger doses of chlorine until you do have enough FC remaining at the end of the day.