Do you want to improve water quality, while reducing sanitizer use and maintenance? Zodiac's Nature II mineral sanitizing products for the pool and hot tub dramatically reduce the need for heavy doses of chlorine and provide an eco-friendly choice for pool and hot tub maintenance. During the regular filtration cycle, water flows through the Nature II cartridge, where a combination of silver and copper minerals destroy bacteria and prevents algae. This process significantly reduces the need for large amounts of chlorine, leaving you with good quality, sparkling, clear water. Who wouldn't love this?