A filter system for spas and swimming pools is disclosed having a primary filter containing a porous membrane made of multiple plies. A fluid purifying medium in the form of irregularly shaped copper and zinc alloy particles is captured between the plies and placed in contact with the spa water to kill bacteria and remove heavy metals, precipitates and chlorine as the water cycles through the filter. A micro filter for filtering particles surrounds the primary filter, the micro filter and primary filter are mounted in a chamber in fluid communication with the spa or pool. Another particulate filter is positioned upstream of the micro filter and primary filter. A secondary micro filter and primary filter provide filter capacity augmentation through a parallel flow path during periods of increased demand.