Went with the Prestone Extreme Duty "silver jug" and will go with distilled water. Too far from a Bimmer dealer to get the good stuff this time. Humorously, When I asked the guy at AutoZone about Phosphate Free, he tried to sell me this "environmentally friendly" propolyne (sp?) based stuff that didn't have phosphates either. No clue-as long as it's aluminum friendly is what I care about. Thanks, Chris