Passive circulation in electrolytic fluid treatment systems

A fluid system (10) is disclosed including a filter system (16) for the moving contaminants from fluid provided by a fluid source (12) to a supplied environment (14). The filter system includes an electrolytic or electrostatic cell (26) which is operated by a control circuit (28). The control circuit is programmed to continue to operate the cell after active water flow from fluid source is discontinued. The cell is designed to passively circulate fluid entirely within the cell, allowing efficient continued filtration to occur. As a result, more efficient matching of the cell to the particular supplied environment may be achieved. Several alternative constructions of the cell are disclosed.