Peggie, I have read the 7/2 Hot water sulfer smell messages and mine is a little different. I have 85 C-30 with the original seaward HW heater. This is my second season. When I bought the boat the water from the hot water tap smelled like rotten eggs. I drained the whole system and never used it. This year, doing more overnighting, I followed your freshwater maintenance and did a thorough flush. Everything smelled fine when I was done, and much to my surprise the heater worked on shore power. One week later the water from the hot water side smelled like sulfer again. Since my heater is not new (like the 7/2 thread)what should I try ? Vinegar flush, bleach flush or somthing else? Thank you Jim