He Fabio, were does the gas get out?
I couldnot find 1 hole in yr endcaps...

Dear Steve, in the last pic you see that piece of antenna at the top of the cell connected to the silicon tube is the gas output but it's tied back to the tank to bubble!
I'm going to make a video to show that better...
One thing I found really interesting is that the hydrogen passing thru the antenna created a zero volt reference point and is possible to measure the electrodes potential in reference to it!!!!!!
One electrode is positive and the othe negative relative to it and surprisingly there is a diferent reading... supposedly the metal should be platinum for it to be theoretically zero volt reference...
This happens because hydrogen provides a determined potential at an electrode it pass into thru...