It is a common misconception that red eyes and a strong chlorine smell to the water is the result of too much chlorine. Actually, the cause is not enough chlorine! The combined chlorine compound, called a chloramine, is produced when a free chlorine molecule combines with a nitrogen or ammonia molecule. These compounds smell bad, irritate the eyes and skin, and get in the way of free chlorine trying to do its job.
How Do I Eliminate Irritants in My Pool Water?
Shocking or super chlorinating is necessary to oxidize, or break apart these compounds. So then, when the eyes burn, and the pool smells over chlorinated, the pool doctor's prescription is to raise the chlorine level ten times the normal amount to achieve "breakpoint chlorination" thresholds which will break apart the chloramine bonds.