Well we have one thing in common mousethief, our hot water tanks packed it in last week, but yours has ours beat, as ours has only been running for 25 years, despite the high mineralization of our well water. It will be interesting too see the inside of the beast, as we believe its capacity and efficiency must be severely diminished after years of calcium build up.

We are going to remain with the tanks system as the tank provides an emergency water source when the power goes out, which happens in the winter here fairly frequently, so that may be another reason you might consider keeping a tank.