Thanks All, again,

I went ahead and bought some CYA and have a small quantity in a sock in the skimmer. Is there a downside to targeting about 15-20 ppm and then letting the pucks bring it up slowly from there? I did have low chlorine (0.5ppm) after this first day after the refill, but it will take a few days to set the chlorinator.

BTW, if I use a cost of $100 per 40 pounds of tablets, that's about 15 cents an ounce, and for a 15,000 gallon pool I've read I'll be using 3 ounces a day to keep 2ppm chlorine, so 45 cents a day. Bleach at Walmart was $2.30 for 1.5 gallons, and a half gallon makes 2ppm chlorine in the same pool, so 76 cents a day. I must be calculating something wrong?

TW