That was what I was going to suggest, but Jan did it first.

Cal-Hypo is usually available all over, as either HtH or the other brand I have a mental block against. If you can get the 62 or 68%, it is better than the 48%--less impurities. But be careful with it--don't mix it with other chlorine types (once in the water it's OK--if you've been using Tri-Chlor or bleach, just use Cal-Hypo instead).