I have a 19,200 gallon pool. Last year was my first year of pool ownership and I used Baquacil. The prior owners used chlorine. This year I've taken this forum's advice and converted back to chlorine. I've shocked the pool, changed the sand, etc. Now I understand what is meant by crystal clear water! On the best day with baquacil, my water was a bit cloudy.

Here are my readings:
FC 0.5
CC 0.5
pH 7.5
Alk 80
Cal 150
CYA <15

I added 4 lbs of CYA just yesterday so I expect to raise it to about 20 ppm.

Anyway, I have several questions:
1. Are these readings okay in general?

2. My CC reading seems to be falling on its own. It was 1.0 yesterday and 1.5 two days before that, without shocking. Is that normal?

3. What happens if CC is too high? Is it safe to swim?

4. When my FC was 0.5 and my CC was 1.0 with DPT, the OTO test result was totally clear. Doesn't OTO measure TC? Shouldn't it have been around 1.5 then?

5. My calcium seems very high. I tested it with an HTH test kit before I had the PS kit and it was 0. Since then I added four pounds of Cal Hypo shock that the prior owners had lying around. Is that enough to increase my calcium to 150 or did I test wrong? Will it go down by itself?

Thanks for your help.