As just said, that is the $64,000 question.
I believe it is generally thought that 30-40 ppm is fine.
There are those here who keep it higher. Way higher.

If you do, you just have to know that the higher your CYA is, the higher your Free chlorine needs to be to do the job, because more chlorine is held in reserve.

Watermom posted a sticky with a chart that will help. I would not freak if your CYA is high, just adjust accordingly. It does go down eventually as water gets splashed out, etc, backwashing, and as rain, etc, replaces it.

Frank D.