I have the rotten egg smell from a new 75 gas water heater tank installed in May ’08. I added a softener/filtration system about a month ago. The tank is in a vacation home used about every other weekend. I contacted the plumber that installed the tank and he said to remove the magnesium rod. He didn’t give me any further advice such as using an aluminum one. What does the rod do and can/should the water heater go without one?