[MoonSailer]

NEVER keep the tank full!!!! Especially if you only use a few gallons a year. A full tank means that the fuel is much older and has sat around growing microbes longer. It is fiction that condensation adds water to a diesel tank. If there is water in your tank it came from dirty fuel or a bad O-ring or some simular defect. Physics make it impossible for condensation to add a significant amount of water to a diesel tank. The Myth of Condensation in Fuel Tanks by David Pascoe: Boat Maintenance, Repairs and Troubleshooting