[QUOTE=DOK;2401463]Lots of good info, thanks guys. I'll check out the dip tube thing for sure. Any thoughts on how to tell how old the bugger is?
You can tell the age of a tank by its seriel no. which can be found on every tank's rating plate.
It varies by manufacturer. On John Wood heaters I believe that it is the last 4 digits gives you the manufactured date. i.e. ...0501 = May 2001.
On some makes it is the first 4 digits.
And on Bradford White heaters, it is a 2 letter code, see this link for decoding details:
http://www.bradfordwhite.com/findaserial.asp
I completely agree that if money is an issue, than checking the diptube is the most resonable first course of action. It is cheap and relativly easy.