I've spent over two hours speaking with customer service reps from American Coach, Spartan and Cummins looking for what I presumed would be an easy answer - what additive to put in the fuel tank of my new 2012 Revolution with a 450 hp Cummins? The local Cummins store suggested a microbiocide (sp?) they carry for $156.65 a quart. Apparently a quart will treat 2500 gallons? The catch was he doesn't carry it and I'd have to buy four quarts. Surely there is a better answer for treating diesel fuel to prevent algae from growing? Would appreciate any thoughts.