Hi, I have just purchased a boat launched in '97 which is in pristine condition. I am puzzled by a nasty water smell when the tap is turned on. After running for a while it is not there. Any ideas of how to rectify? I have inspected pumps and lines under the sink- which look OK to me. Seems to be worst from forward tank. I plan to flush out and treat with a conditioner, is there anything else I should do? 