I'm out of town and my wife had to get the pool water tested at the pool store nearby. They do it for free and never try to sell us anything, so when I'm not around, we use them and when I am, we test ourselves.
They seem to have changed their system and gave her results below (they used to just write down the results on a note paper).
How do I interpret the CYA reading? Should I be using 100 or 50?
I always use these as my guidelines from TFP:
Vinyl with SWG