my hot water smells like rotten eggs. The cold water does not have any odors. Even if I flush out the water tanks, it is back in about 2 weeks. I suspect part of my problem is that I only use the boat on weekends (and often just a few gallons of water are used for washing hands, etc.). The hot water heater is your typical 6 gal size. What is the best way to get rid of this odor? Any ideas would be appreciated.