I agree with everyone else. No need to shock. I didn't need to shock at all last year and maintained the water through the winter and will not shock to open this year as well. As long as CC <= 0.2, there's certainly no need to shock.

The main reason to shock after a large pool party or when children are present isn't just in case CCs develop, but in case there is any sort of accident that might introduce more bacteria or overwhelming amounts of ammonia or other material into the pool. Even with a measurable CC, time and sunlight will likely break it down so shocking is mostly for expediency and extra safety after heavy bather load.

Richard