The sharp “chlorine smell” is usually chloramine, not too much chlorine. Shocking is a measured dose after you test, not a dump of powder on a calendar.
What shock is for
Organic waste — sweat, sunscreen, pollen, a storm — binds free chlorine into combined chlorine (chloramines). Combined chlorine does a poor job of sanitizing and is what swimmers smell. Superchlorination, or shocking, raises free chlorine high enough to break those bonds. A common field rule is to shock when combined chlorine is at or above 0.4 ppm, and to reach a free-chlorine level several times the cyanuric acid factor so the dose actually works in outdoor pools.
How we dose
Test first. Brush. Run the pump. Broadcast unstabilized shock in the deep end with the returns on, in the evening so sunlight does not burn it off. Do not mix products in a bucket. Keep people and pets out until free chlorine is back in the swimming range. If the pool is a salt system, the cell still needs chloride in the water — shocking with liquid chlorine is often cleaner than piling on stabilizer.