Smart Spa Nature Pure Mineral Santizer for Spas and Hot Tubs (Sunpurity alternative) Mineral purification is a natural process that carries out 3 functions: disinfection, algae prevention and clarification Nature Pure mineral spa cleaner leaves water clean, clear and soft Compare to Sundance SunPurity Mineral Cartridge for Spas Reduces the use of chlorine or bromine - simplifies spa care Natural and effective way to reduce bacteria in your spa