I moved into my current house in 2008 and inherited an chlorine pool. I have been having trouble keeping the chlorine levels high enough so I had my water tested. Sure enough, my CYA is over 100. So I am going to drain 1/3 to 1/2 my pool and start over. However I want to use the BBB method as I agree that the pucks will bring the CYA back to a level that is problematic. Wish me luck. Any helpful suggestions would be greatly appreciated. Is draining 1/3 to 1/2 of the pool enough? I was going to turn the automatic chlorinator off and add bleach after I refill my pool.