[prairieschooner]

The reason that "Polishing" the Fuel works well on Yachts is that the Fuel Tanks have Access Plates. If these Access Plates were not installed when new then usually are put into the Fuel Tanks when "Polishing" is needed. The better Companies usually have numerous Empty Barrels to move the Contaminated Fuel into and the Filter the Fuel. The Fuel is used to Spray the Walls of the Tank and knock the Fungus off the Walls of the Tank. Most of the Fuel Tanks in Boats are Aluminum or Stainless Steel.
I don't have Access Plates on our '82 and the Tanks are Black Iron or Steel (maybe someone could clarify) and the Fungus should not stick to it like Aluminum. I like Wally chose to use the microbiocide additive because our '82 sat so long. I also purchased 12 Primary and 6 Secondary Fuel Filters. In the beginning I changed the Primary after a few hours and the Secondary every other time. My thoughts here are that since I don't have the Access Plates (they would be hard to use anyway) and the 6V92 Detroit Circulates so much Fuel we have our own "Polishing" System already. After 5,000 miles all is well, now that I have said something I will replace at least the Primary before we leave for Mexico on Monday. Since our Coach sat in the Desert and others may be in areas with High Humidity I cannot say that this approach is for everyone.
Here is a link to an additive;
http://www.westmarine.com/webapp/wcs/stores/servlet/producte/10001/-1/10001/21560/377%20710/0/FUEL%20ADDITIVE/Primary%20Search/mode%20matchallpartial/0/0?N=377