Dimension One® Vision Sanitizing Cartridge for Spas and Hot Tubs D1Vision Sanitizing System Universal Cartridge A natural alternative to traditional sanitizers, Vision Spa Sanitizing Cartridges give you clean, pure water while avoiding the harsh chemical odors, burning eyes, dry, itchy skin and bleached clothing that are unfortunate by products of traditional Chlorine systems. Using its patented silver catalyst technology, Vision can kill up to 99. 96% of pathogenic bacteria on contact. It is very A natural