Steve, that smell was probably a result of the breakdown of the magnesium anode rod that is installed in the tank. You can take it out and check it to see if that was the cause. It should be installed in the top of the tank. Usually they are covered by a small plastic plug in the top cover of the water heater jacket and the rod itself has a hex head nut that a socket will fit. The rod extends down into the tank and its purpose is to battle corrosion of the heating elements and tank. Some types of water (especially some well water systems)cause the anode rod to break down quickly and when it does you get a “rotten egg” smell from the hot water. Some people just remove the anode rod,cut it off and reinstall the plug but I wouldnt recommend that because it has a purpose. If you get the same problem with your new heater that you said you installedsk a water heater supplier if they are able to get an aluminum anode rod replacement. I have used these before but they are hard to find in this area.Hope this helps!