Nature 2's Spa Mineral Sanitizer provides spa owners with a real alternative to traditional chlorine and bromine sanitizing systems, using its patented mineral-bed technology to maintain spa health. Spa Purifier's formula improves the look, feel, and smell of spa water by reducing the need for sanitizing chemicals, yet does not compromise the overall health of your spa. Use this product after a fresh refill or at start up. Installation is as simple as dropping into your spas filter, and you're done and maintenance is vastly simplified, giving you more time to enjoy your spa rather than looking after it.