A water reservoir and electrolysis cell combination that has a flow connection between a lower fluid port of the water reservoir and an upper fluid port of the electrolysis cell. The flow connection includes a first conduit with an inner bore which serves as a first flow path for the flow of water by force of gravity from the water reservoir to an outlet for the first conduit positioned within the electrolysis cell. The second conduit is concentric to the first conduit and defines an annular space between the outer surface of the first conduit and the inner surface of the second conduit which serves as a second flow path for an upward flow of gas from the electrolysis cell to the water reservoir.