Well my curiosity got the best of me and I cut open my Hydrogen generator today . The direction that came with it called for 2 tsp of KaOH and by the pic I knew he had allot of space but when I took it apart it was 6 mm . I know that he designed it this way for a reason and that at 3 mm or 1.5 one would surely use less Electrolizer . I took it down to 3 mm and started to glue it back together but figured I would wait and see what you guys say ..I know that 1 to 1.5 is supposed to best but I know also the guy designed it the way he did for a reason ..Heat has to be watched as it is a schedule 40 cannister but again wouldn't 1.5 mm spacing and 1/4 to 1/2 tsp of electrolizer have same results ...Plates are + n n n n n - same spacing through out