Fuel polishing - how often?

[rgesner]

Originally Posted by s/v Jedi

If you have a severe and acute infestation, then adding poison obviously helps. That said, in order to prevent trouble and maintain the fuel system, Startron by itself is more than capable. Here is the actual text on this:

Star Tron Enzyme
This product was a clear winner. The tank bottom sample showed some darkening but no pitting. All other samples showed only patina. Early observations led us to add an additional test sample containing Biobor JF (for its biocide) and Star Tron (for its corrosion-fighting) to see if the pairing worked well, which it did. Previously (PS, July 2009), Star Tron was tested against registered biocides including Biobor JF and Valvtect Bioguard. Although the manufacturer does not claim Star Tron to be a biocide, it did show an ability to control biological growth, giving us one more reason to recommend this product. While we have not been impressed with the Star Tron line in gasoline applications, in diesel it seems to be a winner. Bottom line: This is our Best Choice.

You are quoting from the PS test of additives for CORROSION, and Star Tron was indeed their recommendation for corrosion prevention. That it had some effect on growth was a plus, but PS recommended combining Biobor and Star Tron for corrosion and growth control.

In the earlier test for BIOCIDE effectiveness, PS said "Star Tron Diesel is not a bug killer, it is a fuel conditioner and dispersant." and "Although Star Tron Diesel has no pesticides, it held microbes in Sample A at bay for 24 hours." so it had some beneficial effect, however it was not one of their recommendations for growth control. PS actually recommended alternating to different types, because no single product was effective against both tested cultures. They said "to use a borinane (Biobor) half of the year and a thicarbamate (Star brite Bio Diesel or ValvTect BioGuard) the rest of the year. Any formulation of the same chemistry as these would also get our recommendation."

[s/v Jedi]

That's what I mean: Startron is good for prevention. When you have an infection at hand, use biocide to kill them. The corrosion fighting of Startron is directly related to biological growth because both need water. The bacteria grow on the fuel to water interface. When there is no water in the fuel, bacteria can not develop.