OEM SunPurity Mineral Cartrdige - 2 Pack Original Sundance Spas Sunpurity Spapurity Cartridges SunPurity by Sundance Spas provides the ultimate in water purification for your spa for four months. The SunPurity cartridge fits into the bromine dispenser of the filter bays of 880 and 780 Series hot tubs. It reduces the potential for unpleasant odors and residue lines, and can be used with your hot tub ozone system. Lasts up to four months.