Not Carl, but ... yes. Unfortunately, that is the only way to reduce the cya. Even if you do that, your cya will still be 50 which is OK, but you really don't want it any higher than that. As Carl said, at that level, you won't be able to use any more trichlor pucks in this pool or the cya will soon be right back up to 100 again.

I assume, from your post, that you are in the pool industry -- servicing pools? Forum rules are that anyone in any aspect of the pool industry must identify themselves as such in each and every post. By the way, welcome to the forum!