pools
At Clear Comfort I got my introduction to pools. One of my reps had a hotel customer with a pool while I was at Vision Chemical Systems, so I had learned about the awful high concentration of chlorine in most pools by hearing about the standards of maintenance from someone who was following the book.
As my Certified Pool Operator / CPO instructor would ultimately teach me, the standards for chemical error bars are broad; chemicals are allowed to be managed in ranges and are poorly monitored by undertrained and underpaid staff who do not understand the nuanced chemistry constantly changing before their eyes. Also, patrons are poorly informed and accustomed to pools that smell like bleach and burn eyes, skin, and lungs, justified by "it's clean." It's not. Most pools are disgusting. At a bare minimum you should get some test strips and really the gold standard is a liquid kit with reagents and goodies - being a nerd may help you avoid getting cancer.
Why not make use of a super-oxidizer that reduces your use of chlorine AND other chemistry used to balance the chlorine you're using less of? While it turns out, people make up plenty of reasons, I can't think of any credible ones.