Rob, how are you buying diesel fuel and in what quantities? If you are going to the local gas station or truck stop and filling up a couple 5 gallon jugs, then simply buy regular road grade diesel right from their pumps. As you are in Michigan it will very likely be a blend of fuel at this time of year that contains mixture of #1 and #2 diesel. The reason it is mixed, as previously stated, is to prevent the fuel from gelling in extreme cold. Diesel fuel will begin to gel when it is exposed to frigid temperatures, we worry about it with our truck fleet when the temps stay below 10 degrees for several days in a row. As diesel gets cold it will cloud and gel, the fuel filter can clog with a waxy substance if untreated fuel is used at low temperatures and that will have to be cleaned or the tractor engine will not get fuel. Fuel lines also can easily freeze at very low temperatures (our biggest problem from past experience) as the fuel gels inside the fuel lines.
If you buy your fuel in small quantities, you really don't have too much to worry about as long as temps are 10 degrees or above (my opinion, based on my fuel supply from my supplier). If you buy in bulk, and fill your tank in the spring, summer, or even the early fall (before the end of November) you very likely do not have a blended fuel and gelling issues become a real threat as the temps drop. A simple "anti-gel" treatment, available at auto parts stores and most places that sell diesel fuel is probably all you need. Make sure you buy an "anti-gel" as opposed to a "conditioner" when you shop. Many conditioners claim to have anti-gel properties, but they often have minimal anti-gel abilities so you are better off (this time of the year) getting an anti-gel.
