I can't help but wonder what ya'll have to say about the "First Need" water purifier (filter?) by General Ecology. I've seen this particular model on the shelf at REI, it comes with a small bottle of blue dye, and you're supposed to run a drop of dye through the filter prior to drinking the water to make sure that the blue dye gets filtered out. If the dye shows up in the water after the water's been filtered, it means that the filter is "caput." I'm not exactly sold on the "First Need" water purifier because it seems like it would be a hassle to perform the blue dye test every time you need to drink some water. Steripen sounds like a better deal, but I don't know if I'd be willing to stake my life on it. Has anyone ever tried the Steripen? I'm not sure how to categorize Steripen because it doesn't purify the water of toxic chemicals and thus it cannot be called a purifier, but on the other hand, it comes with a solar charger, it's very small and compact, and it doesn't weigh very much, so maybe Steripen is the way to go when it comes to water purification gadgets. LW.