I am not sure where you are located, but we purchased some at our local Whole Foods. It is a high-end grocery store (not one I normally shop ) that also has a lot of natural based items as well. I figured that they must carry it and sure enough they did. We purchased the last 4 bottles.
In any case, that happened to be the first place we checked, but we were basically going to check REI, health food stores, or other outdoor related stores.
Hope this helps!
on Carnival Conquest
July 2005: Carnival Pride
Summer 1985: I can't remember, I was still a kid...:-)