Why look for Dowflake when you are using Prestone driveway heat? That's what I currently use, and have used for several years.
If you find a local source would you pm me the supplier? I am pretty loyal to the driveway heat though.
HD had the Prestone HEET in one gallon containers - I am looking for DowFlake because it can be pruchased in bulk for very little $$$. HEET is (relatively) pricey.
LL