Quote Originally Posted by SunnyOptimism View Post
Your CYA is only going to "naturally" decrease VERY slowly, ~2-3ppm/month at best during the winter.
This statement is not necessarily true. Some pools lose all of their CYA over the winter. We see it all the time. When this happens (CYA biodegrades), you are often left with ammonia in the water as a byproduct and a huge chlorine demand upon opening. No way to tell which pools this will happen to, unfortunately.