Abstract: A hydrolytic cell consists of upper and lower chambers sealed from each other by a divider, with one or more openings in the divider for the passage of gas into the upper chamber. Liquid is prevented from entering the upper chamber by gas-permeable filters such as Hastelloy™ metal filters. Also disclosed is an electrode consisting either of a generally vertical stack of spaced apart perforated disks or porous metal filters such as Hastelloy filters, mounted to a conductive rod. A level sensing system us disclosed, consisting of a light source and detector which directs light into the lower chamber which is reflected off of a reflector within the chamber, such that the liquid level is detected at the level of the detector by a reduced light intensity.