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Reviews > Water Treatment > Solar > Test Report by joe schaffer

Initial Report
by Joe Schaffer

May 21, 2015

NAME: Joe Schaffer
EMAIL: never2muchstuff(AT)yahoo(DOT)com
AGE: 67
HEIGHT: 5'9" (1.75 m)
WEIGHT: 175 lb (79.4 kg)
HOME:  Hayward, California (CA) USA

    I frequent California's central Sierras, camping every month with a goal to match my age in nights out each year; about half the time solo. As a comfort camper I lug tent, mattress, chair, etc. Summer trips last typically a week to 10 days; 40 lb (18 kg), about half food related; about 5 miles (8 km) per hiking day. I winter camp most often at 6,000 to 7,000 ft (1,800 to 2,000 m); 2 to 3 nights; 50 lb (23 kg); 1 to 4 miles (1.6 to 6.4 km) on snowshoes.
Puralytics bag
The Product:
        Manufacturer: Puralytics
        Distributor's web site:
        Product: Puralytics SolarBag
        Received: 5/16/2015

MSRP: $99.99 US

My measures:
    weight: DRY 3 7/8 oz (111 g)
    weight: WET 5 1/2 oz (156 g)
    height: 15 1/4 in ( 38.74 cm)
    width: 9 9/16 in (24.25 cm)
    min. thickness: 2 5/8 in (6.67 cm)
    weight: DRY:  4 oz (105g)
     capacity: 3.5 L
KEY FEATURES: The product claims sunlight activates a "nanotechnology mesh" removing all viruses, bacteria, protozoa and toxins without batteries, chemicals or filtering. This is the only product I have that claims to remove--as opposed to neutralizing--everything but the wet.
    This is a nearly-clear non-BPA plastic bag with a common water bottle-type mouth and closure; containing a somewhat-honeycomb-looking flat mesh occupying most of the flat dimension. The 2 5/8 in (6.7 cm) screw cap affixes to the bag via a plastic retainer strap. The product includes a 4 1/4 x 4 1/2 in (10.8 x 11.4 cm) white bag with an elastic hem at the open mouth to serve as a pre-filter. It looks much like a heavy duty coffee filter; with the elastic gripping the mouth of the bag--well thought, I think. The bag's flat seams are about 3/8 in (10 mm). The top corner opposite the mouth is bonded in a triangle of about 4 x 4 3/4 in (10.2 x 12.1 cm) and holds a large plastic grommet with a 1 1/2 in (3.8 cm) hole.

    I've tried many types of treatments, including wishing, filters, chemicals and UV. I don't tolerate chemicals. Filters can clog, requiring avoidance of water with algae or suspended particles (muddy); or be damaged by freezing. UV doesn't work in cloudy water, and I don't trust batteries. Wishing worked for so long I fear the odds of that continuing to be effective have grown dangerously long. I find no perfect treatment for the types of circumstances I routinely encounter.

    Here is a product that doesn't pump, drain, ask the user to consume noxious chemicals or require technology involving batteries. How can I sleep knowing I've gone so many years without it! Perhaps the answer will be that I can take a long nap waiting for it to work. The manufacturer claims 2 hours in bright sunlight; up to 6 hours if cloudy water or sky. There's supposed to be some kind of indicator that the treatment is done, but I don't know what it is. Thirst?

    Having no way to assess the technical merits, I can only say the bag appears to be well constructed.  I wonder how long the pre-filter will last, and testing may tell. The manufacturer notes an unused shelf life of 7 years for the system, but makes no mention of how long it may last wet. The claim is that it is reusable hundreds of times. If that works out, a bit of math suggests 200 uses of 3.5 L (3.5 qt) = 700 L (700 qt) of purified water for $100 = 7 cents a liter (quart). That's incredibly cheap. One presumes the claim shall prove out. I doubt the bag will survive hundreds of roll-ups and a couple thousand hours of exposure to sunlight, but that in itself does not dispute the output claim.

    Though I'm not going to read any directions, I did accept the manufacturer's invitation to wallow through the scientific reports on the product. I accept without reservation that the product is effective when used as directed (which I'm not going to know).

    At a quarter-pound (113 g) for a treatment system I have to be impressed. Waiting for it to work may require a protocol adjustment, during which time I will suffer the weight of a UV product. Wait time should be no issue on slack days. Perhaps if I can remember to position the bag when I get up for a morning nature call, all will be well by the time my alarm clock goes off (too hot in the tent to stay any longer). It doesn't rain in California anymore; and I prefer camping at the alpine fringe, so adequate sunlight should not be an issue. On days that it is, I'll write the next review.

    It could be mechanically possible to affix the bag to the back of my pack, thereby exposing it to sunlight for the hours I hike. I will never do that.

    An extended family all-nights-in-the-same-spot campout looms on the holiday horizon, a perfect opportunity for the initial wet-test.

Field Report

July 22, 2015
   The family campout got rained out, and I never bothered to wet the bag. I have used it subsequently in CA:
    a) 6-day outing in Emigrant Wilderness, 4 camps--varied from hot and sunny to cooler and cloudy with about 2 days of rain.
    b) 4-day outing in Castle Crags Wilderness, 3 camps--really hot and sunny.
    c) 3-day test on the deck--warm, intermittent sun but mostly shady.
    d) 5-day outing in Carson Iceberg Wilderness, 1 camp--hot and sunny half the time, hot and cloudy half the time.
    e) 1-day test on the deck--several hours of direct sun and a day of clouds.

   It was my intention to keep track of the time; and number of hours of sunlight, cloudiness, shade and nightfall for each fill of the bag. That turned out to be unduly onerous, and so confusing as to be useless in a practical sense. My impressions are therefore "generalizations" of circumstances.

    The Emigrant outing I bolted before reading directions. I waited for as long as a day-and-a-half expecting the treatment medium to turn blue. I'm not sure where I got the impression that it should. In the course of this effort I did fill and empty the bag 4 times, an exercise exceeding requirements later read in directions for cleaning the bag in preparation for use. I always run my water through several layers of paint screen. I was impressed that the bag's filter element removed fine algae; and with how quickly water passes through the filter.

    The first fill in Castle Crags was on a ridge line with direct sun exposure for an hour until sunset at 8:30pm; and then again from sunrise at 5:30am until 10am when I emptied the bag. This time I had put in a drop of blue, and the water was a bit lighter at the end but definitely still blue. At the next site I was in trees, but able to keep the bag in direct sunlight most of the time. I started at 3pm. The water did not clear the rest of that day or by 10am the next morning. The third fill I reduced my expectations to being merely a water lugger.

    For the first deck test I did not move the bag around and it spent much of the 3 days in the shade. At the end of the third day, the water was clear. I thought maybe that would kick-start the process and wake up whatever part of it seemed to be asleep.

    The Carson outing seemed ideal for the product--lots of open sky, direct sun, same camp for 5 days. I filled the bag in late afternoon where it got perhaps an hour of bright sun. The next day it was in the sun for a few hours, then mostly in clouds--not certain the balance as I was gone for several hours. On the second morning the water looked clear enough and I drank it. I refilled the bag and added a blue drop about 10am. Again it took until the second morning before the water looked clear. I filled it again right away. The next morning the water still had a slight blue tinge and I poured it on the campfire.

    The vendor was very helpful along the way answering my emails and offering suggestions, including that he would send another bag if Test at beginningI wanted. He suggested a 3-hour test with pictures. The bag was still blue in 3 hours of mostly direct, midday sun; and much less but still slightly blue after 2 more hours under cloudy skies. The vendor felt the bag was sluggish for unknown reasons, but most likely doing its work. After 30 hours (including overnight) the water was clear as the sparkling Hetch Hetchy tap water I put in.

2nd deck test pictures are: 1pm 0 hours; 4pm 3 hours; 6pm 5 hours.

I was prepared to accept the science and believe in the product. If it met the 2-4 hour target, then I would be satisfied. That time frame is not happening; and the degree to which it is not happening has shaken my faith. I knew I would have some trouble with rationalizing when the bag has had sufficient sun exposure. I was delighted to read there is an indicator for when the work is done; and not so delighted to learn the indicator is the blue drop getting clear. I could use the blue drop every time, but it seems now I'm fussing over the concept of putting in a chemical to know when all the chemicals are removed. (I fuss even more over the necessity of packing the teensie little bottle; and might lose sleep Test at 2 hourswondering what could happen if it leaked!) I think if the blue had gone away in the expected time on a few tries, then I might have developed a "feeling" for when the treatment is complete. Now I'm gravitating back to needing the comfort of an action that makes a definite statement--water through a filter or a light going out. Based on the blue drop experience so far, the time would seem to be from mid-afternoon one day until perhaps the sun goes down the next.

    Thirty hours or so is just not often workable in my routine. If I had confidence in 4 hours, that could work--a few hours in the afternoon and an hour in the morning. The water wouldn't be 105 F (40 C) like it gets after a day in the sun and I wouldn't fret over chemicals (BPA-free notwithstanding) leeching from the plastic in all that heat. I wouldn't have concerns about whether there will actually be sufficiently treated water available by the time I get up in the morning.

     I don't know if I could adjust to using the bag exclusively even if it starts behaving as expected. I Test at 5 hourscarried an alternate treatment, which I wound up using most of the time. I might not mind carrying both if the bag had a few modifications. For example, if it were plumbed with a hose outlet and sprinkler, it could make a worthy shower bag. It's already a good water lugger. Perhaps it could have a zip closure that allows removal of the filter medium when not in that use; and then it wouldn't have to have so bulky a cap as now. In fact, if I continue to use the product after the test period, I probably will make those modifications. Then I have 3 reasons to carry the bag, two of which I can know for certain will always be readily available.

Long Term Report

October 26, 2015

    After further discussions, the vendor sent a new bag and blue bottle. The returned product met test specifications, and the reason why I had the results I got are not evident. I used the new bag beginning 8/27/15.

Field Conditions:

    a) 8/27-9/3 6 days / 2 cycles Holy Cross Wilderness, Colorado, USA. About half the time sunny; partly cloudy with occasional rain.
    b) 9/18-25 8 days / 5 cycles Kaiser Wilderness, CA  Sunny
    c) 10/5-8 4 days / 1 full and 1 aborted cycle Emigrant Wilderness, CA Partly sunny
    d) 10/18-25 8 days / 5 cycles Dinkey Lakes Wilderness, CA Mostly sunny

    On the Holy Cross trip the boys I went with like to hit the trail early and long. The opportunity to use the bag rested on getting it out in late afternoon on those days when the sun was not obstructed by clouds. That only happened once, and once again on a layover day, so two cycles on the bag for a total of 7 liters (7 qt) for the trip, or about a third of my individual need. My alternate, which got used more, was filtering; and to a much lesser extent, boiling.

    The Kaiser trip was persistently sunny and I was able to deploy the bag on a schedule that suits me. I'd get an hour or two of sun on the bag in the later part of the afternoon; and several more in the morning, for a total of 5 cycles making 17 1/2 liters (18 qt) for two of us, accounting for perhaps 40% of our needs. The balance came mostly from boiling and a bit from a battery powered UV product.

    The Emigrant trip allowed only 1 complete cycle on the bag due to overcast skies and timing, accounting perhaps a third of what I needed. The rest came from boiling as chilly evenings gave rise to early campfire. On two days I had only what was left in my coffee pot to start the day.

    The Dinkey trip was sunny 7 of 8 days and provided 5 cycles for about 1/3 of our duo's needs. The rest came from boiling and a bit from a backup UV product which got very obstinate in the overnight cold. This proved a double whammy. One morning was too cloudy to get a cycle completed in the several hours we had available; and the batteries in the backup device would not warm enough to operate the lamp. Up to this point I was feeling pretty good about the bag, but my sunny disposition toward it darkened with the sky.

Adjusting my routine to maximize the SolarBag has not been onerous but also not always possible. I need to remember to fill it up as soon as I get to camp, and to move it around as necessary to keep it in the sun. I like having 3 1/2 "extra" liters (3 1/2 qt) of water on hand even if it isn't always ready to drink. On some days the bag only needs a couple more hours in the morning, and the water heats up just enough to take out the overnight chill. I don't like chilled water, so that suits me. The bag would work better for me if I were to hike early and camp early, but I more often don't rise until the sun boils me out of the tent.

    With two people it's pretty easy to use up 3 1/2 liters (3 1/2 qt) in the morning. Solo, though, it's too much to swill before hitting the trail. I have to remember to go to bed with my trail bottle empty for a chance to use all the water. It offends my sensibilities to pour out treated water; would chafe them sorely to fill the bag less than full; and as much to empty the bag when the sun hasn't provided enough oomph in the time available. The bag (like all of the treatment products I have) has a limited number of cycles and I'm not keen on wasting any of them. Only on layover days could I schedule enough hours on a cloudy or overcast day to get the job done.

    Given the vagaries of Mr. Sun and the length of time required to get water potable, I don't see using SolarBag on an exclusive basis. I carry only enough water to get me to a campsite, meaning I'm often dry when I get there and it's usually late in the day. I need another treatment product to provide ready water. I find little fuss with the bag and like the idea that time fiddles with getting the water done instead of me. Whatever amount of need the bag fills, that is the amount less required from filtering or other treatment options. It weighs about 5.5 oz (156 g) wet. I'm willing to carry that for the certainty of having water lugging capacity even if getting treatment time is not certain. More capacity often equates to availing oneself to great campsites some distance from water. I also like fire when prudent and permitted, and for that one never has too much water on hand.

fuzz    After trying two bottles of blue drops I think they are not a reliable indicator. I can come close enough to estimating the hours the bag has had sun; and I'm thinking if two-to-four hours is the time required, then three hours in the sun for clear water should be good--one in the afternoon and two in the morning. I get a little confused when the sky is less than persistently blue or I'm in trees. I've noticed now that after several hours in the sun clear water gets a slight milky tinge to it. When I see the tinge, I guzzle. No blue drops required.

    On occasion to strain the bag's output after about 14 hours I was surprised to find a residue of cottony fuzz. The next day I strained output after about 3 hours and got the same result, pictured at left. I'm not sure what to think about having drunk this fuzz in the previous 12 times that I didn't strain the output. I'm assuming the manufacturer is aware of this fuzz and that it must be inert, but straining will be an added step. I prefer treatments that take stuff out of the water, not add stuff to it.

    I find it impossible to "know" that water is effectively treated by any of the products I use. If I get sick, I won't know it's from an ineffective treatment. If I don't get sick--never did in all the years of slurping right from the creek--that doesn't prove the product worked. I'm of a mind that one either has faith in a treatment product or not. I've decided to believe in this one based on the company's claims and supporting evidence.

    Perhaps I'm clumsy as I've scuffed two pinholes. Water weight interacts with granite as I fill the bag or move it around for best angle on the sun. I may have fixed that with an application of clear packaging tape on the logo side that I always put down. Both bags I've used seem to have a bit of trouble holding the grommet in place, and the grommet does make toting the bag from a water source much easier. It isn't hard to reinstall, but I do hate fiddling with things or losing them. Perhaps cracking open the Gorilla Glue can fix that. I don't trust the lid loop, and if it did fail, the landing would surely poke holes.

    Being not of a mind to carry a backup filter and having had too many cold failures with batteries, I'm thinking the bag and my backup choice are suited more to summer. Of course filters are subject to freeze damage, so my perfect cold solution remains elusive.

Some questions come to mind for which no information appears evident on the company website:
    a) Replacement blue drops or filter.
    b) Sunny cold weather vs. sunny hot weather performance, same latitude.
    c) Freeze tolerance.
    d) Output fuzz.
    e) Shelf life after getting wet.
    f) Dry or wet storage recommendation.
    g) Shelf life for blue drops.

Quick shot impressions:
    a) light
    b) inexpensive use
    c) presumably thorough
    d) slow

 Thank you Puralytics and for the opportunity to test this product.  This report concludes the test.

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