Our pool was built over the summer of 2015, the pool builders pool school guy told me over the summer months fill the chlorine feeder with 5-6 tabs and leave it wide open. So later that year when it was colder I had the water tested and my Chlorine was up over 14 PPM which is how I managed to bleach out blue quartz plaster. So last June I noticed I was showing 0 chlorine so I went to Leslie's and they confirmed my CYA level was up over 200 PPM so I did a 2/3's water exchange and the only way to keep it from happening again was to install a salt system. Scared to death all last year of doing it again once it started cooling down I turned back the chlorine way down after a summer of 5-6 tabs and wide open. My daughter tested the water Sunday and 0 chlorine, and Leslie's confirmed this time they said it 300 PPM and I need the salt system and to drain the pool. Stopped by another pool store with a different sample yesterday to double confirm the good news. Obviously the pool school guy was way wrong. And if I was going to put a salt system on I wouldn't buy it through Leslie's. I've ordered a K-2006 kit so I can do better testing. I spent Sunday and Monday all over this forum looking at different ideas on what I was doing wrong cause I thought the people who built the stupid pool would know how to run one. The guy I spoke to yesterday told me once I get the pool filled back up to test before adding anything, then turn the feeder back to 1/4 way open with 2 tabs in it and add powder chlorine w/o stabilizer to balance it out as needed. I've read about a gazillion things I was doing wrong on here because I listened to the pool builder.