A few weeks ago, I was preparing for a 4 day hike and put up a post about chlor-floc tabs in addition to the PUR hiker microfilter ($59.95). The microfilter does not eliminate viruses (smaller than the .3 micron filter). Chris K. recommended it and I and my bowel were very pleased. It is easy to use, guaranteed not to clog for a year and filters fairly fast. I was using a two litre container for my water and filled it in no time. Also depending on water quality it claims to filter 200 gallons on one cartridge! That's a lot of tooth brushing! I did however, at the advice of C.K., only get my H20 from the fast moving parts of a stream or creek. I and my dog ate lots o' yogurt, too.<br><br>