Godspeed wrote:

Of course a new tank is "better". But, does it pay to weld a plate?

Since the tanks are in great visual shape, I'm hoping there is a
viable fix-it solution. Does a "normal" welder do this kind of work
or is there a specialty shop somewhere out there like roto rooter or
something?

Most any weld shop can do it. Typical welder is about $75 to $100 an hour +
materials + travel time.

If the leak is on the bottom, it may be difficult to get to. If there is
one leak, there may be others. As I said, it has to be seen to be properly
determined what action to take. It may just be a pin hole leak in one spot,
it may be a pile of rust held together by paint.