For home spa use, an inexpensive, energy-efficient Ozonator is much more practical. The ozonator generates ozone as air is exposed to Very Ultra Violet light, and then injects it into the water. The ozone not only destroys microorganisms, it also breaks down harmful chemicals and causes total dissolved solids to clump together for easier removal by the filter. Ozone also oxidizes combined chlorine and bromine, freeing them to be continuously reused. The result is water which is cleaner, clearer, and smoother feeling to the skin.
Ozone helps prevent the calcium in spa water from chelating, and thus conditions the water.
This is good for equipment and more enjoyable for you. You will still need to use a system such as bromine, chlorine, or Nature 2. With Nature 2, you will probably be able to reduce the amount of shock used. Actual reductions will depend on many factors, including water quality and bather load. To be effective, you should run your ozonator at least 4-6 hours per day.