Thanks for all the detailed responses! I'm pretty much convinced that the resale value justifies fixing the situation rather than ditching the tank
johnshasteen/jsl/arf - this is indeed a Raritan 6-gallon electric only, and replacing it with a newer one with a heat exchanger does sound like the best thing to do. Are you referring to the 1700 series? According to their website it's glass-lined steel rather than fiberglass.
More importantly though, how big of an undertaking are we talking about? Is this still within the realm of a DIY project? Any pointers would be greatly appreciated...
Thanks again,
Amir