Bad news.
Just removed some of the new plates and saw a little rust on them. Yesterday I only filled the electrolyzer with tap water to see if there is any leakage, and then removed the water. This was enough to form the rust. These plates are not from stainless steel. I will have to order a new set of plates from the laser guys. That is sad, because I was ready to do first tests, bu now I can't
At least the bubler seems not affected by KOH as electrolyte.
Thanks.