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Purifiers
There's a simple but critical distinction between a purifier and a microfilter: Purifiers purge viruses, which are so tiny that they slip through the clutches of ordinary water filters. Neutralizing them takes a chemical treatment or a sophisticated extra stage, such as passing your agua through a cartridge containing iodinated resin—which is why purifiers are both slower and more costly than water filters.
General Ecology First Need Deluxe $89
The slow but steady First Need uses a three-stage matrix to draw out and starve viruses. Forcing water through the unit takes extra elbow grease and minutes but ultimately saves you time—because the end product is virus-free, with no need for additional chemical treatment. And because the purifier screws directly onto a Nalgene bottle or filter-compatible reservoir, it's super-hygienic; there's no chance for a dirty hose to touch what you drink.
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Bottle-Style Filters
Squeeze-bottle filters are handy for travelers and day hikers who don't need a large volume of water. I often take one as a backup for my pump filter should I want a bit of refreshment on the run. Be warned,though: Since they rely on squeezing rather than high-leverage pumping, these babies are slooow.
Exstream Mackenzie $50
The eight-ounce Exstream needs a very firm squeeze to force water through its angled nozzle, but there's solace in that requirement: The slow flow rate gives your water dwell time in a cartridge of iodinated resin, meaning viruses go bye-bye. It's great for travels in Third World countries or for dip-and-sip drinking from a canoe. |
Microfilters
Opt for a microfilter if you're convinced that viruses will not be a problem on your travels, or if you're prepared to chemically zap them after you've filtered your water (see "Die, Bugs, Die!"). These get rid of all the other common pests: cryptosporidia, giardia, E. coli, and other bacteria, and they use a carbon element to filter out most chemicals and bad tastes.
Katadyn Hiker $60
You have to like a compact, 11-ounce filter that's guaranteed to be clog-free for a year. That's why the Hiker—originally from Pur, which was purchased by Katadyn in 2001—has been a hugely popular option for nearly a decade. When it does eventually slow down, you just replace the pleated filter component for $30. You also get great volume per stroke; I filled a liter with just 43 pumps. For 2003, Katadyn has given the Hiker a nifty zippered case that includes a slide-lock pouch to isolate the output hose (pristine) from the intake hose (yucky).
MSR Miniworks EX $80
The new 16-ounce MiniWorks EX is an improved version of a longtime favorite, and it's pure MSR. Translation: It's built like a tank (a sturdy, see-through polyurethane canister houses a ceramic filter that should last a lifetime) and easy to maintain (every part can be removed, lubricated, or replaced). This year's redesign utilizes the air that is trapped in the filter housing during pumping to create a spring effect—the action of the handle is smoother and more positive-feeling than ever, and it maintains a steady flow (a liter or so a minute) during both upstroke and downstroke.
SweetWater Guardian Purifier System $73
For sheer pumpability, this is our favorite filter. It moves the wet stuff smoothly, with heaps of mechanical advantage. A clever adapter fits the 11-ounce filter directly to Nalgene and Platypus bottles and bladders. The SweetWater is not strictly a purifier, but stakes a claim in that direction because it's packaged with a bottle of chlorine drops.
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