I just tested my CYA and it tested at zero. The test was not cloudy at all. I've searched the posts on this site and have seen the threads about the anaerobic bacteria that converts CYA to ammonia.
I broke a line a few months back and had muddy water pumping into the pool for a couple of minutes so it is quite possible the bacteria was introduced to my pool.
I last tested the CYA in April and it was at 42. haven 't tested since.
The only thing that puzzles me is that my pump has been running 12 hours a day for the whole time. So it is not like many of the posts I see where thus bacteria shows up after the pool has been closed for the winter.
I am going to the pool store to have the double check my test before I do anything...