Chris - I think I read the same article recently - I passed over it lightly because without definitive evidence I am not taking the "info" as accurate.<br><br>I have read many times for many years that giardia does not treat us all equally... empirical evidence at least suggests that a significant number of folks are not very susceptable to ill effects - but there are many variables (like concentration), so don't read too much into my statement.<br><br>Iodine has worked very well *for me* so far and I've been extended periods with some pretty crummy water. Chlorine has been successful in munincipal treatment practically forever (as those things go) - but without test kits in the field to verify a "safe" residual, I do not have the same degree of confidence. But it worked great - and I can say with certainty that the surface water that was treated with it was much worse then than it is today, at least where I live. I shudder at some of what is documented fact about what used to flow by here... and my memories of the same.<br><br>Filters can work also - I've employed large commercial (almost munincipal level) filters, and of course, ROWPU units (reverse osmosis). But I have no first hand experience with the portable filters, having only read the pros and cons over the years since they became widely available.<br><br>Boiling works great as far as I know. Went about a month on water that was so loaded with organics that it looked like dark tea - we boiled (wood fires) because we felt that chemical treatment would be iffy with all that organic matter to oxidize. No one got sick...<br><br>And I DO strain out the big chunks first! <grin> - but not with my teeth.<br><br>I look forward to hearing more about the claims made in that article - I'm a bit skeptical without proof.<br><br>Regards,<br><br>Tom