First dyno diesel doesn't deteriorate similar to gasoline so what can a fuel conditioner do to prolong diesel's life except help disperse water? Second I never stated JD operators manual as it was a Kubota OM that I looked in to find "no fuel conditioner" mentioned. You must have a good source for fuel treatment because Power Service brand fuel treatment cost $19.95 for 80 oz and that treats only 250 gallons of fuel. Now that's my navel.
Jim, hopefully I am not coming off rude, cause that is not my intention. I was basing my "owner's manual" comments off the JD manual I have and what I have read about other JD manuals. Mine doesn't even bother to tell you that there is a dipstick for the hydraulic fluid for the 2520, nor does it tell you about the nearly impossible to reach u-joint on the front drive shaft of the 2320. I had a Kubota before I went green, and its owner manual was definitely better than JD.
I do have a good source on fuel conditioner among other things (I have a friend that is a distributor/wholesale that I buy from to sell at retail), but I was off about $10, so it is about $50 (retail) per gallon jug that treats 2000 gallons.
As for the lubricity of the fuel, that is going to vary from fuel station to fuel station and the jobber that sells it. I know from personal experience (well not directly my personal experience, but I trust the source) that not all jobbers are honest about what they sell. Most are honest, but there is always that few. I also know the local Kroger's get their fuel deliver by Flying J trucks, but the fuel doesn't come from the same place that the Fjying J and Pilot truck stops get their fuel. I don't buy from dirty fuel stations, it is my opinion that if they don't keep the place clean, then it is probably true about their fuel storage. As for Algae growth, it does take sunlight for it to survive, but there are other microbes that can live in the dark and feed off the fuel and use that little bit of water (there is almost always some water in a tank) that is in your tank for the oxygen it needs to survive.
Is it really necessary to run it? Probably not in most cases. Depending on the area, the fuel may be top notch and maybe that is why you haven't needed to run a fuel treatment (not everyone is going to be that lucky), other areas especially rural, well... I guess that is why I have a 50 gallon tank in my truck, I won't stop at those places. Obviously I recommend it, or I wouldn't be suggesting it as a cheap form of insurance. I have seen what adding a good fuel treatment to a piece of equipment (that has been neglected) will do to fuel filters as it cleans the gunk and varnish from the tank and fuel lines. There are numerous independent studies on the benefits of using a fuel treatment. Fuel treatment is a broad term that can be described in many ways as a cetane improver, detergents to clean your injectors, lubricity, anti-foaming, low temperature operability, fuel stability and so on. The fact that ULSD isn't as stable as its predecessor and tends to break down quicker, but you are right, it is still more stable than gasoline.
