A fuel inspector pops open your diesel tank and sees red diesel fuel inside. Are you in trouble? Depends on what you’re using it for. If it's known that it's being used to fuel your truck, then yes you would be. If you're using it for tractors and generators and farm equipment, then no.
Dyed fuel signifies the presence of fuel that is subjected to a much-lower tax rate than un-dyed on-road fuel. The use of red dyed diesel fuel in most applications other than for home heating use is illegal and could subject the offender to tax evasion penalties.
Back to the hypothetical. So, the fuel inspector opens up your storage tank and see red fuel. No problem, because it’s a heating oil tank and you’re well within the law. In fact, red diesel’s primary use is for home heating fuel and for off-road farming purposes.
What other differences are there between red diesel and on-road diesel? Turns out, not much. Originally, the plan was that off-road farm diesel fuel could be of higher sulfur content than on-road diesel up through December 1st, 2010. On-road diesel had to be ultra-low sulfur fuel (ULSD) with a max of 15 ppm sulfur. Red diesel, the off-road stuff, was allowed to retain a higher sulfur content.
That was the original plan, but that date was extended through 2014 because of practical considerations. We're now almost ten years on, and all farm diesel fuel has had to be ultra-low diesel fuel for the last decade.
If you’re an old-school farmer who was used to getting one kind of fuel for the last few decades, you may not even know that the red diesel you’re buying now has fundamentally changed. You may not also know how that’s going to impact your enterprise.
When that storage tank is opened up, what else might they find besides fuel diesel? If it’s red ULSD, then you’re more likely now than ever before to find microbes and sludge in the tank. ULSD is less resistant to fuel microbes because sulfur used to naturally prevent their growth. It’s not really there any more, and all those tanks of red ULSD are more prone to microbial infection than ever before. Sludge development also goes along with this. “Sludge” is really just made up of the heavier components of the diesel fuel. Healthy red diesel has everything in healthy solution. Introduce microbes, along with longterm exposure to heat and water in the storage tank, and the red diesel fuel becomes unstable, with all those heavy sludge components dropping out of solution and into the tank.
Farmers have enough to worry about. They certainly have a lot of things pressing against their budget without worrying about the red fuel. And yet, here we are with diesel fuel that's markedly different than it used to be. Today's fuels require a lot more care and attention to keep problems at bay. They attract water more easily and are much more prone to microbial contamination than diesel fuels used to be. Luckily, there's a lot of information out there on how best to take care of today's fuels.
That’s why farm fuel professionals definitely recommend a healthy PM program on your stored red diesel. A simple regiment of fuel stabilizer and preventive biocide treatment stops the primary causes of sludge in red diesel and keeps it healthy useable for far longer than not. Farmers don't need much, but their fuel definitely can benefit from these kind of fuel fuel additives.
Better yet, it may be worth adopting a "three-pronged" hybrid approach to your stored fuel care. The right chemical treatments to solve and precent problems, the right periodic mechanical fuel processing to cover the areas chemical treatments can't, and testing to make sure the problems have been solved and aren't coming back.