We have a 10x20 pool in the tropics. Because it is so hot there, lots of nasty things (bacteria etc. ) develop very quickly. Consequently the vast majority of people rely on chlorine to keep things clean. However, there are studies that we have read about the dangers of having chlorine on your body while being in the sun, and how that relates to cancer. We were thrilled to swim in a friend's pool who had the ClearBlue Ionizer. The water was so clean! And there was no chlorine smell! We installed the system in our pool and we couldn't be happier. Mike has been amazing with feedback as the water quality tests have been done. And we are are thrilled with the quality of the product and with the fresh, clean feeling of our pool water.