Buying Right

Review, July 1997
Buying Right

Water Filters That Are Worth the Weight
By Michael Hodgson
Katadyn Combi
You might consider hauling a water filter an unnecessary evil — why bother with the weight and bulk? — but if you were to examine some of that crystalline mountain stream water through a microscope, you'd know the true utility of such a backcountry companion. Think of it this way: It's not unlikely that there's some sort of beast upstream, all too eager to pollute your agua.

Sure, you can kill microvermin by boiling, a waste of precious fuel, or treating it with foul-tasting iodine, which won't affect gut-wrenching cryptosporidium. Neither approach will neutralize dangerous chemicals. On the other hand, running impure water through a filter will at least screen out bacteria and protozoa such as giardia, while some also remove chemicals (such as DDT) and even viruses. The models we reviewed strain large detritus at the intake hose and then send water through a system of microscopic pores so tiny — the most effective are 0.4 microns in diameter — that illness-causing microbes get left behind in the filter cartridge (which has to be scrubbed or replaced periodically). Finally, these filters also remove chemicals with a carbon element.

When choosing a filter, consider convenience of cleaning (all filters clog eventually), ease of pumping, and flow rate, but don't sweat unimportant distinctions like ceramic versus glass-fiber elements. What counts is that while several of these filters will purify potentially viral Third World water, all are safe for any outing in the States, where such dangers are of little concern.

Iodine phobes rejoice! Whereas most filters meeting EPA standards for virus protection use an iodine element, which some folks are allergic to, First Need's Deluxe ($70; 800-441-8166) claims to achieve such purity by filtration alone. Alas, the 15-ounce Deluxe falls just short of perfection with a squat, smooth casing that, though sealed to keep out critters, is tough to grip in less than laboratory conditions: Plunge your hands in glacial runoff and it's difficult to take advantage of the First Need's high water output.

At $185, Katadyn's Combi (800-950-0808) may actually be the best value of the bunch — because it'll be around forever. While most filters pump a paltry 100 gallons before they need new cartridges, the Combi's ceramic filter purifies an astounding 14,000 gallons before it's shot. Built like a billy club, the Combi features a sturdy stainless steel shaft and an ’ber-thick plastic shell, which make this workhorse a tad heavy at 23 ounces. Still, it'll be removing bacteria, protozoa, and chemicals (not viruses) for as long as you'll care to use it.

MSR offers one of the most practical designs on the market in its MiniWorks ($65; 800-877-9677). It pumps water effortlessly; stymies protozoa, bacteria, and chemicals, but not viruses; and is no more difficult to disassemble and rebuild than a ballpoint pen. Hardy doesn't mean heavy, though: The ceramic MiniWorks weighs just 14.3 ounces. Spend $8.50 on MSR's packet of spare washers, O-rings, and sundry parts and the MiniWorks becomes the ideal choice for extended expeditions, when any filter would need regular maintenance.

I've long admired the ergonomics of PUR filters, and the new Voyageur ($70; 800-845-7873) is as thoughtful as its predecessors, with an easy-to-grip textured casing and a meaty handle. The 15-ounce Voyageur uses an iodine layer with a glass-fiber filter to cleanse anything other than, say, heavy water from Three Mile Island. One hitch to bear in mind is that should the cartridge dry out, you'll have to unscrew the top and dunk it to get it primed, which takes all of 20 seconds.

Thanks to a handy lever like those on old water wells, Sweetwater's Guardian Plus ($80; 800-557-9338) couldn't be easier to pump. Like the PUR Voyageur, the 14.5-ounce unit has an iodine layer to kill viruses, along with a filter to remove the usual suspects. It requires a fair amount of field maintenance to keep murky water flowing freely, even with the crud-catching prefilter. Fortunately, however, the Guardian Plus is quite easy to disassemble and clean — a virtue in any filter.

Photograph by Clay Ellis

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