Zander, aluminized steel is basically steel with a specail coating that helps reduce rust. I believe there are traces of aluminum in it, but I am not sure if it will aftect your biodiesel. I think your engine dislikes your grease more than the grease will dislike the tank!
HZJ60GUY,
Are you looking for the 80 series factory sub tank? We should be getting some in hopfully next week, with all this talk on here I think we might sell out pretty quick. I will not be sure of an updated price until they arrive, because of the terrible exchange rate changes.
Thanks a lot,
Steve