The philosophy behind a conventional swimming pool is to kill everything in the water without killing the swimmer.
For example, I learned recently that they treat the water in my local public pool with sodium hypochlorite, more commonly known as bleach. Bleach is a substance I've come to understand I should avoid contact with, so swimming in it seems...counterintuitive.
Thankfully, the next generation of swimming pools are natural and self-purifying, requiring no chemicals to stay clean. With a line of five natural pool designs, customizable for any space, UK company Clear Water Revival is helping lead the charge. Check out the options here.