Hi, welcome to the forum!!
A high CC and lowered CYA over the winter indicates that your CYA was probably eaten by bacteria, which then "poop" ammonia, causing the high CC. It can be fixed, but it's going to take lots and lots of chlorine. Shock level for CYA of 50 is 15 ppm, so you'll meed to raise your chlorine toorabove 15 ppm, and then hold it there until the CC clears. This may take a few days, and WILL take lots of chlorine, but it needs to be done.
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