Sorry for the confusion; I knew to use RV Antifreeze. I sure wish we could use automotive antifreeze, as I have about 10 gallons in the garage...
I ended up using the cheaper brand. The 2902ss took just over 3 gallons, probably half a gallon just to fill the filter canister. For $3/gal, no biggie.
MtnGuy, I too noticed the cheaper had ethyl alcohol, which was listed as the first ingredient. If non-consumable products follow the same guidelines as consumable products (doubtful), then there's more ethyl alcohol than anything else... The premium's ingredients listed "Other proprietary ingredients" at the end.