Black Slime in Fuel/Filter
 

I have an 02 3500 with a 90 gallon Aux tank, about 100k, used to haul a fiver for the summer, It runs about 20 mils a week after that. I usually fill the big tank before my last cheap diesel stop, which lasts me until my next road trip. 2 years in a row during PM, black slime/stringey stuff was found in filter.
Doing some research. our new ULSD seems to attrack water and grow black microbes.
Power Service has 2 products foe this (including a tank cleaner), Star Tron, and I an sure the other usual suspects.
I did a search and found nothing.
Your thoughts, experience, recommendations?
I think s long as the fuel is burned in a short time, say a month, no issue, maybe. I run 2 stoke & Power Service (which is suppose to help with this?)
The last thing I need is black stuff plugging my filters on a long trip.

After some internet research and talking to my brother, I bought some Startron Enzyme fuel treatment diesel additive. They also have a tank cleaner, which I will use after my trip, in the fall. The Startron stuff can also be used on gas stuff, especially motor cycles/ATV's, lawn mowers, etc. which may also sit.
Power Service also has some products, Bio Kleen & a tank cleaner also. I think this type of stuff needs to be bought on line, Amazon is a good source..
My brother has an 07 5.9, and says he suffers from asphaltitis, (something like that), suppose to be more a commeon rail issue because of returning diesel fuel cooking. I believe Gen 2 also has return fuel. This may be another issue.
At any rate, this is something that may be very common. The Startron is similar to Power Service in the other things it does, such as clean & stabilies diesel. I had been using Silver forever, but obviously it did not prevent this problem.

I've had this issue before, as well as excessive condensation in my tank of my box truck.

The issue for me is the minimal fill up's I do. Truck sits a lot. When it does go places, it's short drives. I don't get to completely run the existing fuel out of the truck, and fill up again, as I'm so local with my trips.

So I used the Biocide Killem like you're reading, dumped the tank dry, and filled it up with new fuel after replacing the filter. Good since, but I have to drive it more frequently to replace the aging fuel.

Fuel degrades over time, especially if it's sitting. The black stuff is what is left behind the aging fuel. For me, it's just to replace it more often...