I'm seeing a lot of new threads about water purification systems, and realized it's an area I'm severely lacking in knowledge. When hiking, I've always brought enough clean with me, and planned on boiling if I ever needed emergency water. For Bug In, I would rely on a gallon of Clorex and an eye dropper and/or boiling. So I started to do some research, and now I know less than I did before <img src="/images/graemlins/shocked.gif" alt="" />

Here's what I've found, and what questions I have. This is based solely on the Katadyn web site, since that brand seems to be the consensus choice.

Technology: ceramic, carbon, glass fiber and combination. What does each do that the others don't, and why would I want one over the other?

Nasties: What bio hazards do I need to filter out? Gardia seems to be the boogeyman, but I'm also hearing about filtering viruses. How the heck do you do that?

Capacity: Does that mean how much you can run through before changing filters?

Size: Is there a size that would fit *most* situations short of a full blown SHTF? I'm thinking of something that would work for hiking but also for a few days of camping or home problem scenario. If not, should I be looking at two models?

What questions haven't I asked that I should have?