MSR MIOX Water Purifier — Pocket-Sized Municipal Water Treatment

Great for safe water treatment at base camp.

At last, the MSR MIOX Water Purifier Pen gives us a chance to leave the water filter pump at home! This rugged little gizmo, the size of a magic marker and only a little bit heavier, could purify 200 liters of murky polluted water on a single set of batteries and a packet of salt tablets. Developed for the U.S. military and field-tested in Iraq and Afghanistan, the MIOX technology already proved itself durable and effective. In the civilian version you get exactly what the Army gets, except it’s red.

As with most things, there is some bad news, but it’s mixed and acceptable. The primary problem is timing. Although the specs online mention a 30 minute delay from treatment to drinkable water, if potent pathogens like cryptosporidia may be present, treatment could take four hours.  That four-hour recommendation comes from the instruction manual issued to the military, so make that four hours standard.  The little cryptosporidia won’t wave at you and you can’t tell if they’re there or not without a laboratory. The MIOX pen breaks down a saltwater solution into its basic components of sodium, chlorine and oxygen. The pen user pours that cocktail into a container of dirty water and caps it. Shake it around a bit, sit on your thumbs for awhile, and then test the result, with a test strip included with the magic wand, just to make sure the magic actually happened. You can prepare enough MIOX treatment to purify a half liter, or enough to treat four liters, with one procedure. After four hours even the cryptos give up, inhale the chlorine and die. Plus you get effective neutralization of nerve gas, plague and a host of other things that haven’t as yet escaped into the environment.

Just a couple of little things you'll also need -- and oh yeah, extra batteries.

Lots of other good news comes along with that slightly inconvenient wait. There’s no filtration needed, so you can take that four liters of suspicious water directly out of its source without a half hour of fiddling with the filter pump and trying to keep output away from input. Trying to keep filtered water clean when you’re dirty, the source water’s dirty, and everything else including the canteen is at least suspect, is a tough thing to do right. The sterilizing solution created by the MIOX pen sterilizes the inside of the container, not just the water, and residual chemicals keep the water safe in storage. You can tell it’s good MIOX water because it’ll have that pleasant chlorine flavor. It’s like that Little Rock Municipal water you buy at Walmart, only better.

For water treatment at base camp the MIOX pen is a great idea, and that’s how MSR actually markets this nifty bit of modern technology. If you intend to purify a couple of gallons of water at night, in camp, and then haul it around on the trail all the next day as you backpack, then it’s great for backpacking, too. If you want a fast way to purify a canteen full at a pit stop along the way, you’ll need something else. Of course, that brings you back to a water filter and Steri-Pen, or my favorite solution, an excuse to set up the Svea and boil me up a cup of hot tea while I cook the little buggers out of my next canteen water.

Even with its quirks, at just 3 1/2 ounces the MIOX is like carrying 200 liters of labor-free water. All you need is patience and the foresight to check the batteries, the salt tablets and the test strips before you hit the trail. The salt and test strips come in a Handy MIOX Accessory Kit, and the batteries will be found in any good camera department.

See the Marked Tree A-Store Water Purification section for Steri-Pens, filters and other wilderness essentials.

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About JTHats

Avid backpacker and outdoorsman with old skills and interests in old ways of doing things; equally fascinated by electronics, from the days of Sputnik, to the Zilog Z80A, to the present day of black box circuitry. Sixty years of experience with growing my own food and living simply. Certified electronics technician, professional woodturner, woodcarver, and graduate of two military survival courses — Arctic and Jungle.

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