Why add CYA at all?

[mbar]

The good thing is your pucks will lower your ph and when it gets to 7.2 , you can aerate your water by aiming your return jets up, the alk will lower as it raises your ph. You can continue to do this till you get to the alkalinity of 80 - 120.

[aquarium]

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

[waterbear]

The problem is that as your stabilzier levels increase you need to increase your FC levels to keep enough 'active' chlorine in the pool. You then use more pucks which then increase your stabilzier levels even more.
Check out this thread for info on chlorine levels and stabilzier
http://www.poolforum.com/pf2/showthread.php?t=365