My opinion (guess that is why I am writing this actually) is that fuel tanks
should always be topped up in the winter. The problem when you don't is the
temperature fluxuation. When the tank has an air space in it, and it gets
cold at night, the moisture from the warmer day air tends to condense on the
inside top of the fuel tank. Then the water drips into the fuel. May not
seem like much, but over several months it is amazing how much does
accumulate.
Oh, and be sure to add plenty of a good biocide to the tank to keep the
algae from growing (the technical term -- Microbial Growth). I never could
figure out why any creature would want to live in diesel fuel, but to each
his own.
Chris
