Aspen Times Weekly: PURE Electrolytic Water Purifier

Salt and water fizzle in an electrical bath, a white froth bubbling up. I’m holding a purifying device, my container of lake water ready for treatment on the ground.

A chemical reaction takes place before my eyes, molecules swirling, colliding, creating a new compound inside a tiny slot on the handheld unit.

New this year, the PURE Electrolytic Water Purifier ($119) is distributed by Potable Aqua and sold as the “smallest and most cost effective water-purification device” available.

Its base technology, an electrically-regulated chamber that converts briny water into a microbe-killing solution, has been around for years. But the Potable Aqua device offers a new design and upgrades to a product with roots in municipal water treatment as well as military-backed labs.

Years ago, funding for development of the technology came from sources including the U.S. Defense Advanced Research Projects Agency (DARPA). In the outdoors industry, Mountain Safety Research of Seattle brought to market the Miox Water Purifier, a similar device, beginning over a decade ago.

The Miox product is no longer for sale. But with the PURE Electrolytic Water Purifier you get the same result — a small, battery-enabled unit that manipulates the molecules in water and table salt to create a mixed-oxidant disinfectant of sodium hypochlorite with trace amounts of hydrogen peroxide.

Sounds complex, I know. But in use the device is easy — you pour in a few drips of salt water, press a button to select quantity, then hold the same button to begin the reaction.

It takes a few seconds for the salt water to fizz and change. Pour that solution into suspect water and Potable Aqua claims it disables viruses, bacteria, and protozoa, including giardia and cryptosporidium.

Like chemical tablets, you must wait to drink. The solution takes a minimum of 30 minutes to work, and you need to wait four hours if cryptosporidium is a concern.

Over the summer, I tested the device camping and backpacking with water from lakes and streams. A chlorine smell rises from the device as salt water is converted to its microbe-disabling state.

You charge the PURE unit at home, and its internal battery is cited to provide power for 150 liters of water-purification work. On back, the company built a tiny solar panel capable of recharging the device in the field.

Potable Aqua claims the PURE will treat more than 60,000 liters of water over its lifetime without replacement parts. It weighs a scant 3.8 ounces and is durable enough to toss in a pack.

As far as the competition, pump-based filters offer a faster way to get water, and they can cost less. However, in most cases, filters do not disable viruses, which may be a concern when traveling overseas.

Filters are also not great if you need large quantities of water, as they require a lot of pumping to get a few liters of drinkable water.

The main appeal to the PURE might be that with just a little salt you can make drinkable water nearly indefinitely. Its solar panel makes the PURE self-sustaining, and, once fully charged, the little unit will treat large quantities of water, up to 20 liters at once.

Look into the PURE if you need a way to obtain lots of drinkable water from a suspect source, or if you need an emergency backup that will make nearly unlimited water from a shaker of salt.

Stephen Regenold is founder and editor of http://www.gearjunkie.com.