both sides of a wafer wherein both sides have similar or distinct layer structures fig3 shows a similar approach with a tilt angle 31 relative to vertical 30 imposed on the assembly and the h 2 sweep direction from left to right with this approach the flow requirements may be reduced significantly because of the natural tendency of the evolved hydrogen to exit via hydrogen vent stacks 32 at a minor expense to mechanical complexity because of the additional fluid routing requirements to have all the electrolyte channels flowing in the same direction the chamber may tilted vertical during loading and unloading and filling various other embodiments of this scheme could include vertical reactor with the wafer slots cut at an angle in order to reduce the foot print and also a u201c near horizontal u201d reactor where the wafers are immersed entirely in the electrolytic fluid and the evolved h 2 is carried away by a headspace above the fluid level which connects to a single vent line this arrangement may further reduce the complexity and cost of the h vent manifolding while the upper chamber head space serves as the fluid u201c pressure head u201d in actuality it may be necessary to introduce a pump not shown to provide sufficient pressure and flow throughout the u201c n u201d stack furthermore if the wafer u201c n u201d stack is increased this may further necessitate a pump it may be advantageous in this situation to insure an equal pressure drop from wafer to wafer the pressure difference is necessary to seat each wafer against a seal without sufficient pressure holding each wafer against its seal current may be allowed to leak around the wafers and adversely affect ps formation.