An electrolytic filter system (16) is disclosed for use in treating fluid provided by a fluid source (12) to a supplied environment (14). The system includes an electrolytic cell (18), whose operation is governed by a control circuit (20) to allow a desired average current to be applied to the cell substantially independent of variations in fluid resistivity, to allow the cell to simultaneously achieve, for example, the desired removal of contaminants, killing of biological materials, and alteration of the fluid's chemical characteristics, and to provide relatively high levels of energy to the fluid quickly and efficiently.