ClearBlue ionizer made our gunite pool like a clear freshwater lake in our backyard.  My wife swam almost every summer day. (Prior years: she swam once or twice per season b/c of the stickiness and feel of the chlorinated water).   Balancing was much, much easier; I used 2 chlorine pucks a week in the chlorinator and did not need to shock.  Excellent customer service – ask for Viktoria.     ClearBlue was my BEST purchase of 2020 + 2021.