Since you smell the rotten eggs the most in the hot water, pay close attention to see if you only smell it when the hot is on. Sometimes cetain water will react with the anode rod in the water heater and and cause the smell. If that is the case the anode rod can be removed and that should take care of the problem. The change in salt should not cause this problem: I recently installed a BIG BOSS water softner , I filled it with rock salt it was working fine . after two weeks i switched over to MORTON salt pellets now my water smells like rotten eggs or sewer smell, the smell is really bad when I turn on the hot water. HELP!!!!!!!!!!!!!!!!!!!!!!!!!!! steve