Product Information

Name and model:	AquaStar Plus!
Maker:	Meridian Design, Inc.
Website:	http://uvaquastar.com
Year of manufacture:	2005
Product type:	Battery-Powered Ultraviolet Water Sterilizer
Options:	None available
Ships with:	Instructions, batteries (2x CR123A)
Specified weight:	8.5 oz  (240 g) w/batteries and bottle
Measured weight:	7.4 oz (210 g)
Treatment cycle time (measured):	84 seconds
Projected battery life:	60 treatment cycles
Minimum water temperature:	35 deg F (2 C)
Projected UV lamp life:	2,000 hours
Warranty period:	Two years
MSRP (US$):	$95
Country of Origin:	U.S.
Report date:	December 18, 2005

Tester Information

Tester:	Rick Dreher
Email:	redbike64(at)hotmail(dot)com
Male
Height:	6 ft (1.83 meters)
Weight:	175 lb (79 kg, 12.5 stones)
Age:	51
Location:	Northern California, USA
Years backpacking experience:	38
Backpacking skill level:	Mid to advanced
Backpacking Style:	Lightweight alpine and subalpine travel

Brief Hiking Bio

I learned camping and hiking in Boy Scouts, tramping the Washington Cascade foothills, and eventually took up backpacking as a singular pursuit and found a home away from home in the Cascades and Olympics. Now living in northern California, most of my hiking is in the Sierra Nevada, the trips ranging from overnight to weeklong excursions. Total pack weight for three-day summer trips, including food and water, is now roughly 25 pounds (12 kg), longer trips see pack weights ranging into the mid to upper 30s (17 kg).

[Note: The test AquaStar Plus! is an early production model but should not differ from production models available in stores. Known changes will be noted in the final report. The user guide has already been refined over the draft version available for the initial report.]

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Introduction

AquaStar Plus! is a self-contained water sterilization system that uses ultraviolet light in the “C” spectrum (UV-C) to inactivate biological contamination: viruses, bacteria and protozoa, including cysts. The battery-powered UV generator is essentially a fluorescent tube that inserts into the supplied, screw-top 1-liter (34 fl oz) bottle. It operates immersed in water for about 80 seconds per cycle, during which it renders microorganisms harmless so that the water is fit to drink. The Plus! model tested is the new, second generation AquaStar which features several design tweaks along with an added LED light that converts the water bottle into a lantern for nighttime use.

Field Test Summary

AquaStar Plus! has served as my sole water treatment in late summer through mid-fall--on overnights and day hikes--and it’s performed well. Battery life became an issue on a long trip during which nasty cold nighttime weather prevailed, otherwise it’s soldiered along without a hitch. Between testing and field use, I’ve treated perhaps 12 gallons (48 L) with the AquaStar, alternating between two battery sets, and have also used the lantern function. I’ve operated it using the supplied 1 L (34 fl oz) bottle, a 0.7 L (24 oz) bicycle bottle and a 1.5 L (48 oz) collapsible Nalgene Cantene.

Product Design and Materials

AquaStar Plus! comes in two pieces: a clear, 1 L (34 fl oz) polycarbonate bottle and the works: a UV emitter tube jutting from a threaded bottle cap that houses the batteries and circuitry. The thread diameter and pitch are similar, but not identical to those used in the familiar Nalgene brand wide-mouth bottles.

The bottle is helpfully printed with instructions and graduated volume measurements, including minimum and maximum fill lines for treatment. Polycarbonate isn’t the lightest bottle material but it’s very tough and in my experience, never imparts a plastic taste to water.

The works are waterproofed and protected from physical shock, although the quartz glass tube is exposed and therefore, susceptible to damage from the side (necessary, as covering it would block UV light output). Atop the cap’s threaded portion is an extension with a battery cover on top and the power button on the side. The single button controls all AquaStar functions. Two screw closures on the battery cover can be opened either using a slotted screwdriver or by hand, using foldaway bails. One of the screws sports a rubber hang loop. The circuitry enclosure extends into the bottle below the threaded top and the tube emerges from that extension.

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Two CR123A 3-volt lithium cells power the AquaStar Plus! These relatively common camera batteries reside beneath a battery cover which has molded polarity symbols (+/-). The cover is shaped to only go on in one direction. Note: the battery cover screws aren’t held captive and can be lost.

The user manual has four pages of instructions and helpful FAQs covering nearly every aspect of operation and troubleshooting, as well as the theory behind UV sterilization. Additional information is available at the AquaStar Website.

Purifying

AquaStar Plus! is easy to use:

1. Fill the bottle with any amount from 300 ml to 1 L (10 to 34 oz). Note: don’t fill to the top because the tube displaces some water when inserted, and some airspace is required for agitation.
2. Insert the works and twist closed.
3. Press and hold the power button for about 2 seconds.
4. Slowly invert and return the bottle throughout the treatment cycle—about 84 seconds.
5. When the lights indicate treatment’s done, the water can be consumed.

The treatment cycle can be halted at any time with a button push, useful if simply testing the unit or treating less than the maximum amount.

Prefiltering is called for with cloudy or debris-laden source water. Depending on the type of material in the water, this might be accomplished using a physical filter, settling it out or chemical flocculation.

Low batteries and/or cold water will prevent the AquaStar from completing the treatment cycle. These conditions are indicated by the unit shutting down, accompanied by a flashing red LED beneath the power button. A green LED indicates normal operation. The manufacturer’s projected battery life is about 60 normal treatment cycles, theoretically treating 60 liters (16 gal) of water. The makers recommend doubling the treatment time water that’s cloudy or below 50 F (10 C).

The Lantern

Double-clicking the power switch activates the lantern feature. A white LED shines downward from the cap into the bottle, creating a soft and fairly even glow. The light is dispersed further when the bottle is filled with water. To conserve battery life, the light shuts off after about 15 minutes (dimming a minute before). Each lantern cycle is estimated to use 1/100^th of the battery life, or slightly less than consumed by one treatment cycle. Of course, the light can be switched off at any time.

Field Test Results

I’ve used the AquaStar Plus! extensively and with good success. The only hiccough came when the supplied original batteries failing on a cold, windy evening, after a total of about two dozen cycles. (The air temperature was in the low 20s [-5 C], the water in the low 50s [10 C] and we estimated the wind was blowing a continuous 25 mph [40 kph], gusting to perhaps 40 [65 kph]. Cold!) The treatment cycle would start, but quickly halted after a few seconds, at which time the unit would flash a red failure signal. Simply changing to fresh batteries restored normal operation the rest of the trip. Because it was dark and my hands were very cold, I switched the batteries one at a time to eliminate any possibility of reversing the polarity--even though correct battery alignment is market on the  cover it’s still possible to install them incorrectly.

Out of curiosity I reinstalled the original cells after this trip and they’ve provided another ten or so cycles since then. It may be that in very cold weather, fresh batteries are necessary even if the water temperature is within the target range.

For camping, I’ve adopted a 48 oz (1.5 L) Nalgene Cantene as a treatment vessel. The thread match isn’t perfect--it’s tough to screw on and occasionally leaks--but the increased container volume speeds water collection and treatment for the evening’s camp. Conversely, on the trail I use a slender 24 oz (700 ml) bicycle bottle because it fits better in my backpack side pockets than the standard 1 L bottle. The AquaStar threading fits the cycling bottle perfectly. Both options are lighter than the supplied Lexan bottle, but lack the handy instructions and aren’t as rugged.

I find the green and red LED cycle indicators beneath the power switch difficult to see in direct sunlight, but fortunately the flashing white LED that indicates end of cycle is quite visible. In dimmer light, the colored indicators are easy to see.

For debris removal I’ve used a clean bandana, folded to double or quadruple thickness. It’s not always easy to prefilter this way directly from the source; I’ve found pouring the water into the treatment bottle from another container, such as a cookpot, speeds the job. Fortunately I’ve not needed to prefilter muddy, silty or algae-filled water, which would require more aggressive filtration than a relatively porous fabric provides.

I’ve taken the AquaStar into my sleeping quarters overnight and left it empty, outside. It’s survived several freezing nights without harm, and I’ve leaned to not tighten the lid in the evening so it doesn’t freeze shut. Relatively warm source water means I don’t have to thaw out the works before using AquaStar in the morning; otherwise, a few minutes inside my coat melts any ice and warms the electronics.

Field Test Goals, Answered

I launched this test with several questions:

• Ease of use? AquaStar Plus! is simple and relatively fast. Collecting a couple gallons of water for camp (six treatment cycles) takes about fifteen minutes; collecting a liter on the go takes about two.
• Effectiveness? I’ve not acquired any waterborne illnesses to my knowledge. However, I’ve not performed any bio-death experiments to witness UV’s deadly actions.
• Completeness? AquaStar now recommends rinsing threads with treated water to flush away any contamination.
• Battery life and cost? I don’t have a handle on how many standard cycles are supplied by a single battery set, in part because I’m still tag-teaming the original batteries and one extra set, and in part because it’s difficult to monitor standard cycles due to my using different size containers and the lantern function. Store prices I see for CR123s range from $3 to $10 each; but on-line generic brands can be had for as little as $1 ea. Presuming sixty cycles per battery set, the treatment cost per liter can range from 33 cents to 3 cents, so it pays to shop around!
• Low battery warning? In my experience there’s no advance warning, the unit will simply fail to complete the treatment cycle and flash the red warning signal.
• Lantern function? The lantern is a nice feature. While it isn’t useful for camp chores, it’s a nice shelter light and I can read by it. I especially like the auto-shutoff. 
• Low temperatures? Low ambient temperature affects AquaStar performance, in addition to low water temperature. To combat cold temperature failure I’ve relied on fresh batteries and body heat. Testing cold water performance on day hikes, it has taken five to ten minutes under my coat to warm a liter of cold stream water sufficiently to cycle the AquaStar. I don’t, however, relish the notion of doing this half a dozen times in a row, in camp.
• Wear, tear and ruggedness? No problems so far, either from a couple of inadvertent drops or overnight freezing. The bottle is a little scratched, but the instructions live on.

Field Test Conclusions

The AquaStar Plus! has proven as easy to use in the field as it is at home. Away from the comfort of my Barcalounger I can still operate the controls in the dark when it’s cold and wet. Compared to chemical treatment, the AquaStar imparts no taste to the water and requires no premixing. Compared to pumping, the AquaStar’s fill-the-bottle-and-push-the-button ease and simplicity are hard to match. However, even at 48 oz (1.5 L) per treatment cycle it still takes several rounds to accumulate an evening’s worth of water for camp.

It’s clear that as temps drop battery life drops as well, so I make sure I’ve always got a spare set. Luckily, changing them takes just a minute.

The lantern function is nice around camp and in the tent and because it automatically switches off, it’s especially nice not to worry about falling asleep while it’s running.

Suggestions for Improvement

Use captive screws on the battery cap and tether the cap itself to the works. Add a stick-on thermometer to the bottle.

My thanks to Meridian Design, Inc. and BackpackGearTest for the privilege of participating in this test.

--RTD