The most important thing I learned (the hard way) about electrolysis, after using it for most all of the parts on my 51 Cub that were rusty, is not to hook the wires up backwards! Perhaps my experience will help others not make the same dumb mistake!
I completed cleaning of all the rusty parts last fall, and winterized the 55 gal tank by unhooking everything and covering the tank to keep critters out. Come spring I decided to do one more part: the Touch Control rockshaft. Thinking I remembered the way I had the wires the previous fall, I hooked it all back without checking the wirinng drawing, flipped it on, and let it work for several hours. Didn't look any different on the water surface (rusty foaming as before), but now iron was being removed from the good part and deposited onto the sacrificial rebar. Rust pits that existed before deepened everywhere. The two pivot bearing surface journals which previously were shiny are now rough. Primer and paint have helped hide the surface, but the roughness of the bearing areas still concerns me. Since it only rotates a fraction of a turn at a time, I'm hoping it wont be a problem when I put it back together.
But: be careful to double check the hook up polarity!! Positive to sacrifical anode/ negative to good part to be cleaned.