Grand opening low cya

[Thesil]

Hi all and happy summer season. I started tfp at mid season last year. At pool closing my cya level was 180. All winter I had nightmares about opening this spring and having to drain about47% of the pool. But over the winter the cya dropped to 30. Wow can't believe it! Has anyone experienced this? I was told by forum last year that I would have to drain to get the cya lower. Lucky or what?

39,000 ig vinyl chlorine bleach borax and baking soda

 

[Richard320]

Hopefully that CYA drop was due to rain and snow dilution, and not conversion into ammonia. That has happened a lot this year for some reason. Is the pool holding chlorine okay?