Hey there, I've been thinking about my GHFW and BO bags and I realize that I currently don't have means for disinfecting / purifying / treating / whatever the heck it is you do to water to make it safe to drink. I'm familiar with iodine / chlorine tablets from using them in boy scouts, but as I understand it they have a shelf life of around 4 years? I've done some forum lurking and there seems to be some consensus that in a (sub)urban emergency environment (cough Hurricane Irene cough) one would have to worry about chemical contaminants in addition to the biological ones, which would require the use of a filter. In my admittedly brief search for information about filters I've only really found information about filters for use in the back country, which don't seem to talk about filtering chemical very much (if at all). Really what I'm asking is what kind of treatment is necessary for the kinds of situations one would encounter? Also, (what started this whole line of thought in the first place), has anyone heard of this filter before ( Link and Link )? Good, bad other?