Nature2 Cartridge Filter, Mineral Replacement Cartridge, up to 25,000 gallons (W21500) (W29500)

Nature2 W29500 CF - Fits in side most filter cartridges. Now, Nature is available for your pool. That means you can experience a revolutionary new approach to purifying your inground or aboveground pool that gives you the purest, clearest water imaginable. The patented Nature Purifier uses the same minerals found in nature to trap bacteria and algae. Just drop Nature CF into your cartridge filter, activate the Purifier and let it do the rest for four months. Then, just sit back and start experiencing a more refreshing pool. Nature is not intended for use in aquariums or outdoor fishponds where algae is a necessary component of marine animal health.