Whenever sailors talk about dirty diesel, advice springs forth regarding the best type of filter, the best stabilizing additive for long-term storage, the best additive for cleaning the tank, and sometimes, the suggested biocides for killing the bacteria and fungus that commonly infect diesel tanks. Advice against certain additives is also common, as are products that claim to cure "tank algae," even though they have no real proof of effectiveness.

It is all very confusing. What is certain is that we need clean fuel to keep our engines running smoothly, and to keep fuel clean, it helps to know how it got dirty

Performance boosters from Power Services (white bottle) and Stanadyne are flanked by products from Biobor, Star brite, Racor, and ValvTect. Only the biocides proved effective at beating bacteria and fungi.

in the first place. …