Celebrating over 20 years in the industry, Nature2 purifiers have become one of the greatest success stories, rivaled only by Polaris perhaps. Now owned by Zodiac, (who also owns Polaris) - Nature 2 has expanded their line of mineral purifiers for pools and spas, and also coupled the Nature2 technology of Cationic Sanitation with Salt Chlorine Generators.
Early use of metal ions for pool purification were electric devices, with plates of dissimilar metals, usually copper and silver. Applying electricity to these plates causes the charged metal ions to jump off towards an opposite charged plate, where it is swept away by the water current in the pipe. Use of such systems like Caribbean Clear do have sanitizing properties, but misuse by homeowners can lead to a staining problem. The cells also required maintenance, and the overall system was costly to install.
The engineers at Fountainhead Technologies originally set out to develop a non-electric ionizer. This would be accomplished with a metallic cartridge which would erode itself from the passage of water flow over it, thereby giving off its ions to the water. After years of testing, they had discovered something much more. In operation, the aluminum and silver cartridge causes dissolved oxygen in the water to separate into individual nascent oxygen atoms. These individual oxygen atoms are one of the world's most powerful sanitizers, destroying anything in its path as it tries to re-combine. So, we have an ionizer that also brings a catalytic reaction to oxygen molecules. Sort of like an ionizer and ozonator all in one.
Nature2, and it's competitor the Frog System, by King Technologies don't market these purifiers as sanitizers, nor do they suggest it as a replacement for chlorine. They do suggest that it greatly reduces reliance on and enhances the effectiveness of traditional methods and/or other alternative methods such as ozone. Its performance is enhanced with the use of enzymes.
Zodiac, the manufacturers of Nature2, recommend the periodic use of a non-chlorine shock, and a polyquat algaecide, used in their Non-Chlorine Recipe. Nature2 is more commonly used with a small amount of chlorine (.4 - .6 ppm) quite effectively. This is outlined in their Low-Chlorine Recipe.