Great information Blast.

I went throught the list and I feel that one thing should be mentioned. The MSR Sweetwater Purifier is a rip off.

Ok, take a look at what it claims...if you go to REI.com and check it out, in order to completely purifer the water, you pump it and then add the MSR Purifier solution to the water. Hmmmm...I wonder what the solution is that REI is selling for $10 for a 2 ounce bottle....IT'S BLEACH..holy crap I think to myself. Take a look at a large view of the bottle..it clearly lists the ingredients as Sodium Hypochlorite (bleach) and other ingredients. They are getting 10 bucks for 2 0z of this stuff because the general public doesn't know the good ole chlorox will do it for way cheaper.

So technically...any of the water filters listed could be considered purifiers if they would just include a 2 oz bottle of bleach with each one. Good grief.

Incidentally, prior to PUR selling out to Katadyn, they did manufacture the GUIDE which did have a Iodine based filter that really did purify the water. Hence all the warnings that GUIDE replacement filters will not purify water. I have one and a couple of the filters that have never been opened. Sort of saving them for an emergency if you know what I mean. Was curious how long they might last unopened. Any guesses?