Regarding the statements quoted:<br><br>"you don't even need to boil water for 5 to 10 minutes"<br><br>This is correct. It only needs to reach the boiling point. In fact it actually doesn't need to get that hot but that provides an easy to identify indication that it is hot enough. Nor do you have to "add a minute for every 1000 ft." as was once believed. These are all old wives tales.<br><br>"halogens will not kill Cryptosporidium cysts..." "<br><br>Correct, as noted at http://www.equipped.org/watrfood.htm#WaterPurification<br><br>First Need review is at http://www.equipped.org/watrfood.htm#GeneralEcology. Bit dated but the filter is still essentially the same. I used one for years. Downside is that it cannot be cleaned in the field. <br><br>General Ecology sells a kit with Potable Aqua and their filter. This isn't a bad combo for anyone and covers most all the bases. What most filters will not easily remove is chemical toxins. Even those with charcoal pre or post filters won't entirely clean up some toxins.<br><br>Bottom line is you do the best you can with the available resources and time, use common sense about sources, then drink. <br><br>