First off, all diesel (ULSD) Ultra Low Sulphur Diesel is the same whether it's marked as off road or on road, the only difference is, off road is dyed red and no road tax is levied on it.
Secondly, all diesel has a percentage of Soybean based 'bio diesel' in it by Federal mandate.
Thirdly, when diesel sits in a storage tank, whether it's at the fuel station or in your bulk tank or in your fuel can or in your fuel tank, it's getting older and the older it gets, the more likely it is attracting moisture and the moisture is what grows algae. Most bulk storage tanks will have some water in the bottom, which is why fuel sticks that they use to check the level are treated with a special coating that shows the water content in the bottom and modern storage tanks have electronic water monitiors built in so the water can be drained out.
Consequently, the best alternative is to add a biocide to ALL your fuel, all the time. Don't take much to prevent an issue. I believe Powerservice has a biocide in it. Not sure. Why I use Bio-Kleen all the time. There are others out there. I've used Caterpillar biocide before but the Bio-Kleen is easier to get and it's all the same stuff, a algae killer.
I learned the hard (and expensive way). It cost me north of a grand to rid my diesel pickup of it and I did the work myself. Had to drop the fuel tanks, drain them, replace the lift pump, replace the sending units and replace the fuel bowl and many filters. At least the filters stopped it from getting to the pump and injectors because if it gets in the pump or injectors it destroys them.
Don't matter to me, I just use it 100% of the time now. Cheap insurance. I turn over my fuel pretty quick as I farm so I'm using quite a bit of diesel, but dor people who don't use a lot, a biocide is like money in the bank.
My 2 cents, take it or leave it, your choice. Your wallet.
Black fuel is algae, plain and simple. Really bad algae is stinky black fuel with chunks.