Charles, I don't disagree with anything you've said, and I'm certainly not a chemist, or any other kind of expert in fuel analysis. However, with gasoline, I've had some personal experience that was enough to convince me that "fresh" gasoline runs better than old gasoline, although old gasoline will still run in an engine. Does Stabil help? I don't know, but a lot of people claim it does and it doesn't cost much. /forums/images/graemlins/wink.gif As for your analogy with the cape buffalo, I agree. But you're talking about one salesman. With diesel fuel, we've heard from people who had it gel in cold weather, I've personally seen algae grown in my own diesel fuel, and even my wholesale fuel distributor, and many others have told me that no additive is needed IF you're going to use it all in a month or so, but that it would be a good idea if you're going to keep it longer than that. So, I'll readily confess to having no technical knowledge, or even any knowledge of a good statistical experiment, but once again, Power Service didn't cost much, all my "real farmer" neighbors used it, so I did, too. Did I waste my money? Maybe so, but as with your cape buffalo repellant rock, I didn't lose a lot of money, and it provided some degree of peace of mind. /forums/images/graemlins/wink.gif /forums/images/graemlins/laugh.gif