Thank you Watermom. I haven't even tested the CYA level yet since I don't have one yet lol! I guess once I get this in the pool I'll test it after about a 1/2 hour?

Then according to the Ben's Best Guess chart, say if my CYA is at 20ppm, my chlorine shoudl be no less than 2 put no more than 5? Just want to make sure I'm reading it right.

Then what does the "Shock" and +Shock+ column numbers mean?

Thanks!
Julie