I have searched for the answer to this question, but my apologies if I missed it somewhere on a forum. I have a brand new Fiberglass pool 12,000 gallons. It has an automatic Chlorinator that uses those Trichlor pucks. All my pool builder has done to start up the pool is load the column with pucks and turn the dial to 2. We tested the water and the PH was 7.4, and of course chlorine was 0. I had tested it twice in 12 days and still got 0 for chlorine. I have shocked the pool at night twice now and in the morning chlorine is still 0. Today I have shocked it twice ( I am using a granular fast dissolve shock that says to use one pound) and still 0. My question is.......even though my auto chlorinator has pucks that have CYA, shouldn't I add some CYA to help hang on to the chlorine during this startup phase? My water is very clean and sparkling......just put a new filter cartridge in ( the old one was extremely dirty from the install and all the dirt and concrete that got into the water). I admit I haven't checked any other parameters. My kit he gave me just checks for chlorine and PH. I don't even know what chlorine it is checking for, total or free or combined. How long does it take before the Triclor pucks with their CYA is enough to balance the pool by themselves. I skim and vacuum and keep the pool spotless everyday, so it does nor have a big bio load and no swimmers at all yet. Thank you inadvance, for any help you can give me.