For lightweight--- to get all pathogens, bacterium, cysts, and viruses, you can try what bentoworld does. He uses the 2oz filter straw
http://www.backpackinglight.com/cgi-bin/backpackinglight/aquamira_frontier_pro_filter.html in water that has been treated 15 minutes (all that’s needed for viruses) with chlorine dioxide tablets.
For me, I don’t like waiting; I filter right out of the cold stream and drink it. Also, I don’t have to carry as much water that way.
The biggest questions I have about filters are:
1. How do you know if the cartridge broke? This could come from a light shock or freezing. You will never know.
2. Are there any independent studies of how well the filters perform?
And because of those questions, that’s why I still stay with First Need. They have a test (the blue-dye test) that ONLY works with their filter but the easy test let’s you know ‘your filter is cracked!’ (which has happened to me). Also, they’re the only filter you can find published independent test data on--- not just a stamp that says ‘meets EPA standards’.
Some things I have learned:
-An extreme nicety about the First Need is its all one piece; nothing to assemble at each water hole. Thus it is easy to keep the contaminated portions away from the clean portions.
-The Hiker Pro will clog before the First Need does. I think the Hiker Pro needs a much better pre-filter.
-First Need is 16oz for these niceties, but that’s lighter than carrying water.
-Barry