It's hard to tell a good pool guy from a bad one. They all show up once a week, smile, and seem to be doing something to your pool. But the truth is that most pool guys do not understand the chemistry of pool water and are often doing things to ensure that your pool water is perpetually out of balance. Many pool guys have not received proper training and keep your pool out of balance inadvertently, thinking they are doing the right thing. Since your pool guy doesn't swim in your pool, he won't know that your eyes sting after a swim, and since he won't be around in a couple of years, he won't know or care that your surface is wearing out prematurely.