I re-ran the test twice more, once diluting by half, then diluting using 1/3 pool water and 2/3 RO water. The last test indicates that the CYA is 270.

We live in the upper-midwest, and when the pool was opened in May, I had the water tested and I see that the reading at that time was 60. Is it possible for it to raise that much in less than two months? Also, I used the pucks all last season, so why was the CYA low when we opened in May? I will see if I can figure out how to just use bleach. If I have questions, I will do my best to look for the answer first.

Thank you in advance for the advice and help.