SO IN RESPONSE TO SOME OF MY DISASTER-PREP WRITING, I got a package of HTI Hydropacks in the mail. They’re supposed to be like a Capri Sun for disaster relief. You drop the pack into dirty water — basically, anything short of raw sewage or industrial waste — and after twelve hours it’s full of something clean and gatorade-like. I’ve got one floating in a pot of water now; I’ll report on how it works out.