I wrote an in-depth review of the MSR Guardian water purifier last summer. Since then I’ve consumed about 150 liters of water pumped from streams and lakes, out of its rated life of 10,000 liters. It is a full-on water purifier which removes bacteria, protozoa and viruses.
While the MSR Guardian is superb (see my video on my review page on how it is used), I’ve ordered a SteriPen to try out (never used before so I cannot speak to its efficacy from personal experience as yet), because it is much more compact, and sometimes my North Face Recon daypack is stuffed so full of gear that I cannot carry the MSR Guardian.
I am curious about one of the company’s claims: that it removes viruses. have you seen a review anywhere that confirmed that claim by actually testing it? if yes could you please send me the link? I’m not saying that it can’t be done, but it’s a big claim and a big part of justifying the price.
DIGLLOYD: the claim is misleading in this sense: the SteriPEN removes nothing. Rather, it kills the nasties with UV light. I had a conversation with a reader some months ago, this reader having used it extensively and he is confident that it kills the nasties quite effectively, including viruses.
Personally I would much rather use a true water purifier (not “filter”) like the MSR Guardian water purifier because it not only removes bacteria, protozoa and viruses, but also removes crud: sediment, mosquito larvae and whatever else might be in the water. The issue is that the MSR Guardian weighs a pound and is the size of a 1L Evian water bottle, so it is often problematic to squeeze into my pack and I have gone (very) thirsty on some all day hikes when I did not bring along two full liters of water (one liter is never enough in the high country).
A water filter option is the LifeStraw Personal Water Filter. It is very compact and weighs hardly anything. I have one, but I have not used it as yet. And it does not remove viruse, which is probably not an issue in the high Sierra, but would be an issue with poor water quality in some areas.