The only problem I see is spacing. Your anode and cathode are far apart and current is restricted to the small tubes they have to travel through. You could add lye until the resistance in the water stabalizes. Meaning, measure the resistance in the water, add lye until that resistance wont decrease anymore. You would do better to put the anode and cathode into the same container and seperate them with a plastic plate. That way you could have the plates close together but still have them produce separately. Thats alot of water too, I was using about 4 teaspoons in about a gallon of water which is about 4 liters.
2006 Ram, 5.9 cummins HO. 4 cell design, 1.5 LPM@30amp, 24.3 MPG