Electrolytic rust removal seems to be a bit of a fad right now. I'e used it occasionally over the years, and it works fine, but no better than simpler chemical or mechanical methods.
Electrolysis is essentially a line-of-sight process, so the electrode needs to be inside the tank. Any baffles in the tank will be a problem. Tanks with odd shapes can also be a problem. The effectiveness of the process is worst in areas hardest to see, so there is often a false sense of success.
Electrolysis is a good tool for specific situations, but it's way down the list of rust removal methods, at least for me.
Ed