VPI cleaning fluid and fungus


Does anyone know what the VPI cleaning fluid is made out of? I have a bottle that has been sitting for a few months, unused. I looked at it today and in the bottom there is a 2"X1" fuzzy grey-green ball that looks suspiciously like a huge ball of mold. Now, that can't be good for my vinyl. Granted, all of the fluid should be vacuumed off, but this still concerns me. Is this just a bad batch of cleaning fluid? Should I switch brands?
jt101
Did you refrigerate the solution after opening it? I've been using the VPI solution for several months now without problems. The instructions with the concentrated refill state that, after mixing with a gallon of distilled water, it should be kept refrigerated.