What would "shock level" be considered?

I've been reading but can't seem to find the answer. Last year it was hard to hold my chlorine level. It would go from 6 to 2 overnight. Hopefully it won't happen this year. I believe my CYA was in the 30 to 50 range. What I've learned here is to hold a shock level until the chlorine loss stops. My question is what is proper shock level?

Thanks
Cooper

Depends on what your CYA level currently is. See the Best Guess Chlorine Chart in my signature below.

Thanks Watermom!