I get all of my Taylor refills at Amato Industries. Same day shipping and order process updates via e-mail. The direct link to the product you're looking for is here for the 2 oz. They also carry it in 16 oz which is what I buy. Amato is located in MD.

Another vendor that's mentioned occasionally is SPS Pools&Spas in IA. I like the layout of their ordering pages a little better than Amato's.