I want to make Randy's diy recipe for calcium dosing but can't seem to find the recommended products. Dow flake doesn't seem to be available anywhere local. I'm checking Home Depot/Lowes for Prestone Driveway Heat and it's not available in any store which customer service said may mean they don't carry anymore. They have other options for calcium chloride but I can't find any information on people having used them in reefs before. Any recommendations on where to buy an adequate substitute in Brooklyn?? I'm aware there are online options but would prefer local pickup before I end up ordering anything.