Quote Originally Posted by sabres07 View Post
As a point of referrence, I was told I had 'chlorine lock' a few years ago by my pool store after having the same problem you are having now. No matter how much chlorine I added it would get eaten up almost immediately. So I googled chlorine lock and found this site....I have not set foot in a pool store since then and my pool has been crystal clear, too, since I have been following the BBB method. By the way, it took something like 30-35 gallons of 12% chlorine to kill whatever was causing my chlorine demand. We eventually figured my problem stemmed from a degredation of CYA over the winter which created ammonia as a waste product. Vast amounts of chlorine are needed to rid the ammonia.
I also had to deal with the effects of CYA degradation this spring. I estimate I lost about 40ppm of CYA. It took about 26 jugs of 8% bleach before CL levels stabilized. It's been smooth sailing from there.