You need to keep your chlorine at shock level until:
1) You can go from sundown one evening until within one hour of sunrise the next morning without losing more than 1ppm of chlorine
2) You have no higher than a 0.5 CC reading
3) Your water is clear

Then, you should keep it at shock level for one more day for added insurance. Then you can let the chlorine drift down and keep it in the proper range based on your CYA level.