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SteriPEN Adventurer Water Purifier REVIEW

A reasonably light and very effective means of purifying water to EPA purifier standards.


Overall Rating: Recommended

The SteriPEN Adventurer gets a Recommended rating on several grounds. It is quite light, it works faster than the competing technologies of filters and chemicals, it handles viruses which filters generally don't stop, and there are no chemical residues to worry about. In addition, most chemical treatments have problems with protozoa such as Giardia lamblia and have to be left for a very long time to be fully reliable, up to hours on end for some chemicals.

It doesn't get a Highly Recommended rating because it is still a little heavier than could be and it is a bit hungry on batteries. Should a similar unit come out which uses UV LEDs instead of the gas discharge lamp, I suspect it might achieve our highest rating, but the technology may take several years yet to arrive.

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by Roger Caffin |

SteriPEN Adventurer Water Purifier REVIEW


There is nothing worse than getting sick while out walking, and one cause is contaminated water. A big problem is you very often do not know whether the water in front of you is safe or not. There may be 'bugs' in the water: very small viruses, middle-sized bacteria or largish protozoa. There are four common ways used to convert water of doubtful quality into something you can safely drink - or to make those bugs harmless.

  • Boiling - takes a lot of time and fuel, leaves water hot or tasting 'flat'
  • Filtering - does not take out the very small viruses
  • Chemicals - do not always work reliably, may take hours to be effective 1
  • UV light - as reviewed here

Boiling, though it consumes fuel and time, is very effective if you do it as part of cooking. Filters can be heavy, have limited filter life and with one exception filters do not remove viruses. Since those little rotaviruses (for example) are responsible for a lot of dysentery, it is unfortunate that filters let them through. There are a lot of different chemicals on the market for treating water, including iodine, chlorine and chlorine dioxide, but they all have the serious problems of residual smell and taste. In addition some by-products of these chemicals are not very nice.

The chemicals do work quite well against most viruses and bacteria and are very widely used for this purpose. However, their efficacy against protozoans (such as Giardia lamblia and Cryptospordium spp.) in cyst form2 is questionable within the short contact times suggested by most manufacturers (< 30 minutes). This is because protozoa have a very hard shell around them a lot of the time. This concern has been validated in the United States during the failure of various chlorine-disinfection facilities in water distribution systems, with protozooan outbreaks as a result of short contact times. The risk of outbreaks in Europe has decreased dramatically in recent years, and this may result from increased efficacy of chlorine dioxide against protozooans in cyst form. Unfortunately, little research has been performed to understand why chlorine dioxide may be more efficacious against cysts. Early findings suggest that, unlike chlorine or iodine, chlorine dioxide's molecular structure is able to permeate the cyst wall without becoming inactivated.

Lacking a quick, perfectly effective chemical treatment, we are left with UV light, which has been used to deal with 'bugs' and purify water as far back as 1910. It has been used commercially for applications such as bottling plants and extensively for chemical-free community water supplies, and its popularity is increasing. However, you should note that UV treatment has no effect on any chemicals which might be in the water - especially nasties like agro-chemicals, solvents and so on. You will need to watch where you get your water from - but you're probably doing that already.

What’s Good

  • Effortless operation
  • Lighter than any filter
  • Works for all bugs to EPA standards
  • Treats 1 litre (1 quart) in 90 seconds
  • No chemical smells or residuals
  • Can use rechargeable batteries

What’s Not So Good

  • It isn't cheap
  • It relies on batteries, which it loads very heavily
  • Batteries are a little expensive (but cheaper than most filter cartridges)
  • I worry about breaking the quartz lamp cover
  • Solar Charger is a bit heavy - an overkill design



Hydro-Photon Inc


2006 SteriPEN Adventurer


  • Basic Unit with Lamp cover and batteries 101 g (3.56 oz)
  • Nylon Sheath 28 g (1 oz)
  • Two spare CR123 Lithium cells 31 g (1.1 oz)
  • Solar Charger 160 g (5.64 oz)
  • Foam cover 26 g (0.92 oz)


  • SteriPEN Adventurer 160 x 40 x 23 mm (6.2 x 1.5 x 0.9 in)
  • Solar Charger 180 x 90 x 35 mm (7 x 3.5 x 1.3 in)

  SteriPEN Adventurer Case

Plastic, non-slippery

  Lamp housing


  UV wavelength

254 nm, in the deep UV-C range

  UV transmission

Negligible through common plastics and glass

  System Control

Embedded microprocessor with safety interlocks

  Estimated battery life

About 60 L (60 qt) for 2 non-rechargeable cells in warm weather

  Solar Cell Area

130 x 55 mm (5 x 2.2 in)


US$129.95 for SteriPEN Adventurer; US$49.95 for the solar charger


A serious caution should be given here as this whole area of water treatment or purification is a minefield. Each vendor of a purification product will present a threatening analysis of the water problem and a glowing analysis of the effectiveness of the product he or she is selling. Unfortunately, while the sales pitches may be fairly truthful they are not always complete. I have found that the bits which get glossed over or left out are sometimes rather critical. Well, I guess no manufacturer wants to tell you the bad bits. Also, there is a specialised jargon involved, as discussed below. It can all be very confusing.

However, I am also aware that some products on the market are relatively ineffectual, and others use a lot of 'weasel words' in their claims. The manager of AccuFilter went too far and ended up in jail in 1996 for fraud after being prosecuted by the EPA for the second time. On the other hand, the information provided with the SteriPEN Adventurer seems complete and credible.

In real life many walkers never bother treating their water: they are just careful where they get it from - and they survive. If you combine this caution with the UV treatment, you should be doing well.

Method of SteriPEN Operation

Each photon of UV light contains some energy, and if the wavelength of the UV light is short enough the energy can be sufficient to cause a change somewhere in the chemical bonds inside the bugs. For instance, if the bug has DNA, the UV light can cause the thymine bases in the DNA to lock up with each other, which prevents the bugs from replicating (breeding). In general, if the bugs can't breed and multiply inside you, they can't do you any harm. Of course, you need fairly energetic photons for this, but light in the UV-C band can do this. A common source of this is a discharge lamp emitting at 254 nanometres (nm), although some fluorescent lamps can also be used. The EPA has a lengthy document 3 on the whole subject, although it is primarily focused on industrial-sized systems.

Large discharge lamps with adequate power came first; very small ones with enough power were developed only more recently. The SteriPEN uses one such small UV-C lamp, which looks very similar to the Philips TUV4T5 Germicidal Sterilamp used in the Aquastar product. The SteriPEN Adventurer uses a microprocessor to control the operation and is powered by two CR123 (photo) lithium batteries. The company claims the lamp will provide at least 9,000 effective doses of UV but to be on the safe side they have limited the operation to 5,000 doses, and the unit gives a warning when you have passed 4,900 doses. They can replace the lamp. I would add that 5,000 doses is a lot of water treated.

Effectiveness of UV-C light and the SteriPEN Adventurer

It's no use taking something which is not going to work. Those home-made gravity-powered filters using a plug of cotton wool may be very light and very cheap, but they are not going to stop any viruses, nor any bacteria, and probably won't stop protozoa. They might make the water look clean and give you a happy feeling, but that feeling might change to unhappiness a day later if you get dysentery. There are EPA standards for water purification which are designed to protect your health, and it is wise to use a purification method which meets those standards. In passing, you should note that while many filters meet the EPA standards for protozoa and bacteria they do not normally meet the standard for viruses. Only a product which meets the EPA standards for all three sorts of bugs can qualify as a 'purifier': the use of the word is legally restricted in this context.

It has long been known that UV light can disable viruses and bacteria. Up until recently it was thought that UV light could not kill protozoa, but in the 90s it was found that researchers were asking the wrong question. UV light does not 'kill' the protozoa, but it does stop them from reproducing inside your gut, and as explained above if they can't breed they can't hurt you. Once this was understood the popularity of UV-C treatment for community water treatment started to rise. However, some non-UV water-purification companies still do not even acknowledge UV treatment as an option.

While this may be getting a shade esoteric, field tests have shown that our waterways are starting to show traces of certain hormones, antibiotics, fragments of recombinant DNA and RNA and other complex biological agents. They are coming from industrial processes, agricultural wastes and sewage treatment plants. I have seen data that suggests the same UV radiation will incapacitate some of these nasties as well.

The big question then is whether the SteriPEN Adventurer meets EPA standards and whether it has EPA registration. I asked the company about this, and they replied:

While our company is registered with the US EPA (company number - 73679), the EPA does not certify non-chemical water purifiers. As SteriPEN uses no chemicals it is not certified by the EPA. Non chemical systems such as ours and filters may be tested to the EPA standard. If these non-chemical systems meet the requirements of the EPA protocol then their literature generally states "meets US EPA protocol."

According to the Lab Test Reports I have read the SteriPEN Adventurer (and the older Classic) do meet the EPA requirements for treating all three sorts of bugs, and the SteriPEN Adventurer is advertised as a 'water purification device.' Backpacking Light has no means of running the very complex biological tests required for this so we will rely on the work of the independent test labs. I am satisfied by these reports.


Steripen - 1 The SteriPEN Adventurer.

The pre-production prototype unit we received is shown here. The main difference between it and the production version seems to be the direction of the printing by the button. The black and yellow body holds two CR123 lithium (photo) batteries and the electronics needed to drive the UV lamp and control the operation. The little red arrow at the bottom of the picture points to a small pushbutton, which is the only control on the whole unit. The little green arrow to the right points to a LED which shines either red or green. The blue arrow points to a metal electrode: there is one of these on each side of the unit and they sense the presence of water. Somewhere inside the unit there is a lamp temperature sensor. The long glass tube is a strong quartz envelope enclosing the UV lamp itself. When traveling it is wise to put the cover over the lamp: it clips on very firmly.

To operate the unit you remove the cover from over the lamp, press the button once (for 1 litre) or twice (for 0.5 litre), and put the unit in the water to be treated. The metal electrodes must be below the surface of the water. The lamp comes on and stays on for the required time, then turns off. You are advised to stir the lamp around in the water a bit to make sure you irradiate all the water. The length of exposure depends on the number of button presses and the temperature of the unit; the microprocessor will calculate this for you. The variation in dosage time due to temperature is not large. There is some variation in efficiency of UV generation with temperature. The UV action on the bugs is not significantly affected by the water temperature.

The manual or booklet which came with the pre-production version had very brief operating instructions on page 3, while the rest of the booklet was devoted to marketing waffle. This is a pity - a smaller booklet with better instructions would have been appreciated. It may be that the production version will be better. Ultra-lightweight walkers may take some exception to the ridiculous claim on page 2 that 'With the SteriPEN Adventurer, you're carrying hundreds of gallons of pure water in your backpack ...' However, maybe I am being too harsh.

Safety Matters

Steripen - 2 Blue Light coming from the lamp - or not, depending on the angle of view.

If exposure to the UV light can bump off the bugs, what will it do to you? This is the obvious question. This was addressed in a document entitled 'Common Questions' which I received, but I am not sure whether this document normally ships with the SteriPEN unit. As the document explains, UV light will not go through either glass or the common plastics; these materials block the UV. In addition, the company says the UV light bounces off the water/air interface at the top of the bottle.

In the pictures to the left the discharge can be seen in picture A, but it seems to be missing in picture B. In the case of picture B the lamp is still on, but the viewing angle from above is such that the blue light is being reflected off the water/air interface. In picture A you can see the blue light, but this is visible blue light, not the UV-C light. The UV has been blocked by the glass wall of the bottle. You can see visible blue light from the top of the water. The company claims that the UV light will not escape in this way but will rather be reflected off the water/air interface. They claim to have checked this with a UV light meter.

Another obvious concern is the effect on your eyes if you could turn the unit on before putting it in the water and got the UV in your eyes. Well, you can press the button, but the microprocessor has a mind of its own and for reasons of safety won't turn the lamp on until it senses water at the metal electrodes. For this to happen the lamp has to be underwater. So far so good. If you take the lamp out of the water while the UV lamp is running the microprocessor will detect the loss of water and shut the lamp off in about one second. It will also turn the LED on with a red colour as a warning that the treatment time was not completed. However, it takes about a second or two for the loss of water to be sensed, and in this time the UV light may be shining in your eyes, so don't pull the unit out of the water while it is turned on!

So why can't you put the unit in the water first, before pressing the button? The reason is again safety. It would be safe enough if the lamp really was under water, but this may not be so. If the bottom of the unit is wet from the last immersion, the water sensor can be fooled into thinking that the unit is under water even when it is out of the water. The unit could be fooled into thinking it was safely under water and thus turn on in your hand as soon as you press the button - and blast your eyes. To prevent this the microprocessor has a rule that the water sensor must be 'dry' when you press the button for it to work. There is a trap here: if the bottom of the unit is still wet from the last immersion when you press the button, the unit may refuse to operate. You may have to brush the sensors dry with a bit of rag before you push the buttons. I was caught a couple of times like this.

Field Testing

This unit may have only one (input) button and one (output) LED, but it does have a microprocessor inside it, and using it sometimes seems almost as complex as programming a VCR. Well, not quite, but I found the following 'features' from testing and reading the User Guide.

  • You have to turn the unit on before you put the lamp in the water.
            That is, putting the lamp in the water first does not work!
  • Pressing the button once turns the green LED on, first steady, then flashing fairly quickly.
            The unit requires quite a definite press of the button to work: it is not hair trigger
  • Pressing the button a second time makes the green LED flash quickly anyhow.

  •         However, I can't tell beforehand whether it has been set to treat 1 litre or 0.5 litre.
  • The green LED goes off when the UV lamp goes on.
            But if it flashes slowly while the lamp is on it means you are between 4,900 and 5,000 cycles: a warning.
  • When the treatment is complete the LED will either flash slowly (for 1 L) or just stay on (for 0.5 L).
            More importantly the UV lamp goes off, which is much more noticeable.
  • If you take the unit out of the water before the time is up the UV lamp goes off within about 1 second and the LED glows red.
            but putting the lamp back in the water does not turn the UV lamp back on.
  • If you leave the unit turned on in the air, it will time out after about 15 seconds and turn off by itself.
            It is supposed to give one red flash when it times out.
  • Red flashing is obviously a warning, and has two meanings:
            fast flashing: low batteries - flashes for 8 seconds.
            slow flashing: lamp has done 5,000 operations and should be replaced.
  • You can cancel the operation when the LED has turned red by pressing the button for a moment.
  • You must dry the two sensors before you try to treat the second batch, or it may think the unit is in water still.
            This can be a real trap if you are not thinking!
  • Getting the lamp cover off is hard work: do it carefully so you do not break the lamp!
  • There is no residual disinfection property like with chlorine and iodine.
            More care may therefore be needed to keep the treated water clean.

Steripen - 3 Putting the SteriPEN in various water containers: it does not work with small-necked PET bottles.

Not listed above as a feature is the speed of operation, but that is because it is worth a separate comment. I have used most of the available filters over the years, and they take time to set up and then you have to sit there and pump for a while. That is, if you don't have to stop and clean the filter half-way through. The pumping can be hard work. With the SteriPEN Adventurer I just sit there and stir gently for 90 seconds. Well, to be honest, my wife often does it while I do other things. With chemicals it does not take long to drop a pill in the water, or to mix Part A with Part B, but then you have to wait for 15 - 30 minutes (or more) before the water is safe. When you are thirsty, this can be a long time ... I find I can wait the 90 seconds for the SteriPEN Adventurer fairly easily.

I did find that the SteriPEN Adventurer does not fit into every possible water container. In particular, it does not fit down the neck of my favourite ultra-light PET water bottles - which come free with every 1.25 litre bottle of fizzy mineral water. So using the SteriPEN has meant I have had to change how I treat our drinking water: now I do it in our cooking pot, with continuous stirring. I can pour the treated water into a bottle later. Mind you, since the lamp radiates out sideways rather than downwards the shape of the pot is just right for the light distribution from the lamp. I don't think trying to treat water in a tall thin bottle is a good idea anyhow as the bottom region would not get much light. Alan Dixon has used a wide-mouthed hydration bladder for treating his water, as shown in the middle picture here, but the height of the bladder could be a problem. I don't suggest you do it this way.

You should note that pouring water from one bottle into another after UV treatment is not without a risk: there is no residual purifying action once the lamp has been turned off. With Coghlans iodine tablets I know there is a trace of iodine still in the water which can handle later contamination. Since I currently use the same type of PET bottles for treated and untreated water, I have to be very careful to distinguish between the two (I put a spare rubber band around the neck of the treated water bottle)! Still, I can always use a little bit of the treated water to rinse out a 'contaminated' bottle; the chance of a harmful number of bugs being left in the bottle after doing that is very low.

Needless to say, my testing has been done on fairly clear water. After all, if the water is so turbid you can't see through it then the UV light won't get through it to the bugs either. It may make some sense to filter any mucky water through a bandanna or similar first - or to find better water if you can. But more importantly the presence of a small amount of dirt or organic matter in the water will not greatly affect the operation of UV light. This is very different from using a chemical, where organic matter in the water will soak up the chemical and may leave the bugs alive.

The User Guide recommends you do not use the SteriPEN when it is at a temperature below freezing. There are two good reasons for this. The first is that water below freezing may be ... ice. Bit hard to stir the SteriPEN Adventurer in a block of ice! The second is that battery life for the 3 volt CR123A lithium cells does fall badly below freezing as shown in the graph below, and you need to look after those batteries. You may be aware that the Eveready e2 1.5 volt AA and AAA lithium cells have much better life in the cold than this, but that is because they have a different chemistry. The SteriPEN Adventurer is quite small, so it is no hassle to stick it in your pocket for a while to warm up.

I have found that people are sometimes more willing to use UV disinfection than chemicals because they want to avoid both the smell and taste of the chemicals, and to avoid their by-products. This is not a quantitative assessment, but for many walkers it is a real issue. One thing I can say is that the SteriPEN Adventurer does not seem to alter the taste of the water at all. This method of UV treatment may be the wave of the future.


With the SteriPEN Adventurer you are dependent on the life of the two CR123A lithium batteries, and those little batteries are not cheap. A good pair of these will cost in the region of US$12 - US$14, although cheaper ones may be available (with less life). You can also use the unit with rechargeable lithium cells, and the company sells a padded carry case with a built-in solar panel on the lid for recharging. The company claims that the cost of operation amounts to about 11 cents per gallon (4 liters) purified with rechargeable batteries, but I have no idea how much they are paying for their batteries, and prices and quality can vary widely. Testing was done with both the rechargeable CR123A cells and the readily available standard CR123A non-rechargeable lithium cells.

Steripen - 4 Life of a CR123 under pulsed load (courtesy Duracell).

The current drain from the batteries starts out at about 1 Amp: this is a lot for the little CR123 cells. Fortunately they were designed for photographic use and can take that sort of load in short bursts. After about a minute, when the lamp has warmed up, the current drain drops to about 0.9 Amps. This represents a load of about 2.7 Watts (per cell), and typical battery life at that sort of continuous load is about 0.85 hours to 2.0 volts and 1.0 hours to 1.55 volts. I do not know the minimum voltage which the SteriPEN Adventurer will operate at as this is a little hard to test. However, this does not matter very much since when these cells reach their end of life the cell voltage falls quite fast.

With a pulsed load the life of the CR123A cell is longer, and we can treat the SteriPEN as a pulsed load, albeit a fairly harsh one. Using a graph from Duracell, we can see (thin blue cross hairs on the red line) that at 0.9 Amps and a low duty cycle the life of a cell can be as long as about 1,800 x 3 seconds to 2.0 volts, at 'room temperature' (RT). This is 90 minutes. The SteriPEN Adventurer takes about 90 seconds to treat 1 litre of water. This suggests that one set of CR123A Lithium cells will treat 60 litres of water, at 'room temperature.' At US$13 for two cells, that is about 22 cents per litre. I can't tell you how many days walking this translates to as everyone's water use is different. Remember that if you are going to boil some of your water for cooking, you do not need to treat that part with UV first.

The graph also illustrates the very bad effect sub-zero temperatures have on battery life! You can happily use the SteriPEN Adventurer in the snow if you warm it and especially the batteries up to body temperature first.

Steripen - 5 SteriPEN Adventurer battery compartment.

Replacing the batteries in the field is very simple with the SteriPEN Adventurer. The end cap is held in place by a screw, but this has a huge head with a huge slot (red arrow) which I can operate with my thumbnail or almost anything. It does not seem to jam at all. Undo the screw and the cap comes off. The batteries just slide out. Insert new ones with the small terminal pointed upwards as shown in the picture and replace the cap - there is a small retaining lug at the right hand side of the picture below the green arrow to hook in place. If you forget and put the batteries in upside down it does not matter as nothing will happen. There is a shaped contact at the tip of the green arrow which will only mate with the small battery terminal; it won't connect with the large terminal at the other end of the battery. I won't say it is foolproof, but it comes close. Check that the new batteries work by pressing the button. The green LED should come on. You can either now use the unit to purify water or just leave it alone. After a little while (about 15 seconds) the microprocessor will get tired of waiting, flash the red LED once and then cancel the operation.

If you are going to store the unit in the drawer for a long while between trips you are advised to take the batteries out during storage. I found the unit does draw a few milliamps when turned 'off.' This is because the microprocessor is running all the time, obediently waiting for your next command. This takes power. It is easy to take the batteries in and out between trips. The metal screw on the cap engages with a metal nut on the body (rather than plastic), giving the fastener a long life.

Steripen - 6 SteriPEN Solar Charger, open and shut, showing solar panel.

Solar Charger

The SteriPEN Adventurer will also take two rechargeable 3 volt CR123A batteries, but recharging these requires a special recharger. I have not seen any suitable generic rechargers on the market, but SteriPEN sells a solar-powered recharger for these called the SteriPEN Solar Charger. The charger's case will also protect the SteriPEN Adventurer and comes with a foam cover (not shown) that can be tied onto the top of your pack. The company says the Solar Charger can recharge a pair of the CR123A cells in about 2 days if the sun is good, but if you recharge the batteries every day it certainly won't take that long to top them up. For instance, if you have treated a few litres of water in the evening it should charge up with an hour or two of reasonable sunshine the next morning. I am not sure how one tells when the batteries are fully charged this way, but I gather the Solar Charger won't hurt the batteries.

This is an interesting concept, but the empty Solar Charger weighs 160 grams (5.64 oz) while a pair of spare batteries weighs only 30 grams (1.06 oz). Each pair of rechargeable batteries will treat about 50 litres (100 pt) of water. The extra weight of the Solar Charger seems an unnecessary burden while walking - in general you would be better off taking spare batteries. I have yet to consider giving the Solar Charger the 'UL treatment' to reduce its weight for very long thru-hikes - that would of course completely void the warranty.

The Solar Charger can also be driven by a universal plug pack from the mains, and this option is far more useful in my opinion. The plug pack can take anywhere from 90 volts to 240 volts, which means it can be used around the world. (Australia, where I live, uses 240 volts). The plug pack has pins for an American wall socket, but adapters can be bought. The plug pack connects at the hole in the side of the Solar Charger shown with the red arrow. There is a red LED beside that hole: this glows brightly while charging, and dimly (if at all) when the batteries are fully charged. I guess it measures the current flow. This option seems to me to be the one I will use most of the time.

The Future

Frankly, I think that disinfection by UV has enormous potential for outdoors use. The current 'wand' may be a little heavier than we would like, and certainly the drain on the batteries is fairly severe. Within a few years I would hope to see suitable UV LEDS being available, and I am sure the company will be very eager to release an LED-based wand with ten times the battery life, running off two lithium AA cells. When this happens I want to see the UV light shining downwards into the depths of the bottle rather than out sideways as it does now. I can dream - in the meantime this unit works fairly well.

Ideally, when the new unit is introduced a new lighter solar panel might accompany it. This should be a flat unit consisting of just the solar cells, with a power lead coming out and a small socket on the new wand. That way you could recharge the cells in the wand while you walk.

What's Unique

  • No chemicals - no taste (feature shared with Aquastar unit)
  • No long waits (feature shared with Aquastar unit)
  • Lightest UV treatment unit on the market
  • Comes with field recharger

Recommendations for Improvement

  • Move to UV LEDs
  • Have the UV light shine downwards into the bottle as well as sideways
  • Reduce current drain
  • Switch to two lithium 1.5 volt AA or AAA cells
  • Lighter Solar Charger panel, scrap the case


  1. eg Chlorine dioxide at 5 C (41 F) against Giardia and Crypto.
  2. Vendors of different chemicals may try to dispute this, but that's what comes out of independent academic research.


"SteriPEN Adventurer Water Purifier REVIEW," by Roger Caffin. (ISSN 1537-0364)., 2007-02-28 03:00:00-07.


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SteriPEN Adventurer Water Purifier REVIEW
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paul johnson
(pj) - F

Locale: LazyBoy in my Den - miss the forest
Re: Re: LOG Reductions in Untreated Water on 03/21/2007 05:15:41 MDT Print View

My apologies for not being clearer in my prev. post.

I had an over 3page reply ready exploring a number of different assumptions and various avenues of logic, but who would read it? I didn't even want to proof read it myself!!!

Since i'm so bad with words, let me try numbers and let me take just one part of my never-to-be-published voluminous reply...

Let's go with 5 drops (each drop 1/20 of a ml) on the threads - perhaps(???) more realistic than 5 microliters (physical properties of water at work here, hence my choice of a drop vs. a ul). Let's talk bacteria here since that's what the other Poster had mentioned. Please note that the case is worse for protozoans even in treated water *IF* the water is highly contaminated.

Using the 1 per ul figure from the other Poster's post...

conc./ml, vol. in ml, total #, reduction factor, remaining #
treated: 1000 1000 1000000 0.000001 1(remaining)
untreated: 1000 0.25 250 1 250(remaining)

Add the 250 viable oraganisms back into the liter (as was suggested for the purposes of illustrating the statistics) and drink the liter of water. Has a sufficient disease causing "load" now been ingested? Depends upon a number of factors. This was part of my point on the use of statistics to play a statistical numbers game vs. using non-statistical sort of "real" numbers. My point on flawed logic was just a theoretical #'s game that seemed obvious to me upon reading the other Post that the other Poster posted.

Does this help to explain my difficulty in understanding the meaning of the other post? I'll admit that I'm not the sharpest tool in the shed. What am i missing?

Also, check CDC & FDA/BBB websites. #'s for Giardia & Crypto MUCH lower than quoted by another Poster.

Giardia: "Infectious Dose - Ingestion of one or more cysts may cause disease, as contrasted to most bacterial illnesses where hundreds to thousands of organisms must be consumed to produce illness." [taken fr/ FDA/BBB]

Crypto: "The infectious dose is low; ingestion of as few as 10--30 oocysts has been reported to cause infection in healthy persons" [taken fr/CDC]

Crypto: "Infectious dose--Less than 10 organisms and, presumably, one organism can initiate an infection." [taken fr/ FDA/BBB]

BOTTOM LINE (for me, personally): i'm going to continue to use my UV-C purifiers. I trust them.

Edited by pj on 03/23/2007 04:05:38 MDT.

(RobertM2S) - M

Locale: Lake Tahoe
Steripen on 03/21/2007 08:09:38 MDT Print View

Re: "How about wiping off the threads with an alcohol pad after drying with a cloth?." I like that idea. An even tastier option might be to use a little Jack Daniels. And when the little wifie complains about the 5th of whiskey you slipped into the bottom of her backpack, simply explain that it is a vital part of the water purification process.

John Garberson
(Montana) - F
How UV Works on 03/21/2007 17:47:40 MDT Print View

I understand the benefit and efficacy of UV treatment to be the 'inactivation' of the bugs in the water. The UV radiation disrupts the replication DNA so that the nasties can't reproduce. Whatever 'living' bugs are ingested do not blossom into populations capable of causing disease.

This from a Canadian consumer site;

"The ultra-violet rays, similar to the sun’s UV but stronger, alter the nucleic acid (DNA) of viruses, bacteria, molds or parasites, so that they cannot reproduce and are considered inactivated. UV treatment does not alter the water chemically as nothing is added except energy. It should be noted that inactivated microorganisms are not removed from the water. UV treatment does not remove dirt and particles, metals such as lead or iron, or hard minerals such as calcium. Other devices are required to remove particles, metals and minerals..."

In bouncing around from reference to reference trying to understand the theory behind UV water treatment I find a lot of commentary about the "inactivation" of nasties but not a lot of use of the word,"kill." I have seen phrases such as, "...killed or rendered harmless." Perhaps the answer lies in one reference I found, "If the cell cannot reproduce, it is considered dead."

If the SteriPen gets a little smaller I'm gonna bite... :)

Victor Karpenko
(Viktor) - MLife

Locale: Northern California
Re: Re: Re: LOG Reductions in Untreated Water on 03/21/2007 21:48:41 MDT Print View


Here is some more data to back up your conclusions. There has been a lot of studies conducted on water quality here in the Sierra Nevada and Yosemite.

Another report from Stanfurd states that the San Francisco PUC tests for Giardia in both source and treated water at least quarterly and has occasionally (about 23 percent
of the time) detected very low levels of Giardia in
the Hetch Hetchy, East Bay, and San Francisco
Peninsula source waters at an overall average
level of less than 12 Giardia/100 liters of water.

This would indicated that if you were in the Yosemite area, Hetch Hetchy, that you would have 0.000007 cysts in those 5 drops that you left on the threads.

Here is a quote from this web site:

One conclusion of this paper is that you can indeed contract giardiasis on visits to the Sierra Nevada, but it won’t be from the water. So drink freely and confidently: Proper personal hygiene is far more important in avoiding giardiasis than treating the water.

First, an excerpt written by a highly regarded wilderness physician:

“In recent years, frantic alarms about the perils of giardiasis have aroused exaggerated concern about this infestation. Government agencies, particularly the United States Park Service and the National Forest Service, have filtered hundreds of gallons of water from wilderness streams, found one or two organisms (far less than enough to be infective), and erected garish signs proclaiming the water ‘hazardous."

Here is a picture of the nasty creatures:Giardia

Edited by Viktor on 03/21/2007 21:54:02 MDT.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Re: Re: LOG Reductions in Untreated Water on 03/23/2007 01:37:50 MDT Print View

Hi pj

> Giardia: "Infectious Dose - Ingestion of one or more cysts may cause disease, as contrasted to most bacterial illnesses where hundreds to thousands of organisms must be consumed to produce illness." [taken fr/ FDA/BBB]
Hum - the references I saw use a threshold of ten, not one. Ah well, just one log unit ... :-)

> Some viruses can multiply in the squamous epithelial cells lining the intestines, viz. so-called intestinal "flu" of viral origin. Who here in the Forums has never had a so-called 24-hr intestinal "grip"/"flu"? Please raise your hand. I learned in class that these are often of viral origin.
Yep, such things exist, but by the time you are a responsible adult you have probably developed *some* resistance or tolerance. And, as the name implies, after 24 hours your body has usually got on top of it - unlike some of the other bugs.

But, you know, there are hordes of walkers out there who never treat their drinking water at all - and they survive. One wonders, while staggering up the hill with all that heavy expensive water treatment gear on board, whether the risk is quite as great as the vendors of the same expensive water treatment gear claim... Dunno.
Me, I wash my hands with a little bit of soap and water every time, and before I prepare dinner.

paul johnson
(pj) - F

Locale: LazyBoy in my Den - miss the forest
Re: Re: Re: Re: LOG Reductions in Untreated Water on 03/23/2007 04:25:25 MDT Print View


I'd have to agree with you. For decades my friends and i drank freely of water sources here in the NE. Sometimes we'd get some mild intestinal problems - often at home, or rarely on the trail. Was it from the water, or did we acquire it at home either b/f or aft. the trek? Probably no way to know without a stool examination.

Only started treating the water when i "learned" that i should treat it.

Even with water treatment methods "on board", so to speak, i still pass on still, stagnant, smelly, suspect sources *IF* at all possible. Just the smell and taste(???) alone (chemicals from either decomposition or agriculture) makes me want to pass - even if i could eliminate any and all biological threats.

I think that out this way with a greater farm density and lower elevations our water sources MAY have a chance of being more contaminated than high up in the mountains out west in the USofA.

Oh, BTW, i've removed some of my prev. comments. Don't know what i was thinking putting just that info there - very misleading and to a degree just plain wrong; as it didn't represent accurately the spectrum of lower intestinal ailments. That's why i checked in here, and found your reply, as it popped into my head what i wrote to you and it was very misleading, it's not really the direct reason one gets the runs - my apologies.

As far as "one" - check the quotes i excerpted and placed in the prev post. The words "presumably" are there assoc. w/"one". The indicates something good and possibly something bad. More good than bad perhaps. I guessing that what they're thinking of is a particularly virulent strain and a person who has poor resistance. Again, the theoretical is often what is expressed even if, practically speaking, the chances are extremely small that such would occur.

paul johnson
(pj) - F

Locale: LazyBoy in my Den - miss the forest
Re: Re: Re: Re: LOG Reductions in Untreated Water on 03/23/2007 05:06:58 MDT Print View


you're right (and Roger is, again, certainly right - IMO).

protozoans usually have much lower concentrations than bacteria - some protozoans feed on bacteria - food chain stuff and what a food chain can support. in fact, even the 1 per ul is probably(???) higher for bacteria than one will usually find in the wild (i'm more familiar with potable well water than surface water where it's much lower - 1 per ml or less, typically).

while researching (finally starting to use the web more for this; thanks guys for teaching an "old dog" a new trick) i came across a study that found from many samples that 10 protozoans per liter were demonstrated in untreated water - pretty low numbers.

i know from ponds sometimes i've found at least one in every drop, or at least one in every two-to-several drops - much, much higher concentrations, but then i was selecting my sample in what i thought was a location that would be higher in conc. of the lil' buggers since i wanted to see which ones where there - not representative of what would be in the water source i would select, if at all possible, for drinking water while on a trek.

Oh,...the other thing i want to make clear is that wiping (and dipping a point of absorbent pac-towel, etc. into tighter places in the cap and allowing capillary action to draw up the water) the threads of bottle & cap and merely absorbing the hypothetical FIVE DROPS, leaving trace amounts, blows the numbers that i was expressing away. Essentially, very little and close to nil would be left.

i still y'all out west might have cleaner water (lower farm density and higher elevations) than we have in NE.

paul johnson
(pj) - F

Locale: LazyBoy in my Den - miss the forest
Re: Re: Re: Re: LOG Reductions in Untreated Water on 03/23/2007 05:06:58 MDT Print View


past few days Forums have been extremely slow for me with 5-10 minutes elapsing (without timeouts) when displaying Forum pages or Posting.

Closing Browser window via the normal fashion (closes immediately indicating that Firefox is not "locked up") and opening another, sometimes shows that Posts have been posted, other times not.

Think problem is on BPL server end.

Edited by pj on 03/23/2007 05:12:04 MDT.

Douglas Frick
(Otter) - MLife

Locale: Wyoming
Re: Re: Re: Re: Re: LOG Reductions in Untreated Water on 03/23/2007 10:43:28 MDT Print View

>past few days Forums have been extremely slow for me with 5-10 minutes elapsing (without timeouts) when displaying Forum pages or Posting.[...]Think problem is on BPL server end.

I haven't noticed that. Unlike normal, where I go through and read everything once every day or so, the last few days I've been 'working' so I sit here and refresh the Recent Posts list and read the new posts every hour or so. Haven't notice any performance problems with BPL at all, i.e., no more than 10 seconds to load a page at any time.

Sorry for going off-topic.

The discussion is, of course, interesting. But pragmatically, I'm not going to worry about it because the chances are extremely low that I'm going to get sick with any reasonable choice in water treatment, even if there are a few unsterilized drops. My spoon is probably a larger threat. I have a fair selection of water treatment options, but the number one reason I take the UV AquaStar (3.8 oz including batteries), except in winter, is that I can drink cool fresh stream water in the mountains as I did when I was a kid carrying only a plastic cup. I dip a liter of fresh stream water, zap it, and drink it. No flavor change, no chemicals, no wait. Depending on the location and time of year I might bring something to pre-filter the water, but most of the places I hike have clear streams. Just lucky, I guess. The AquaStar fits nicely on a 1L lexan Nalgene bottle (4.7 oz), but it also works on a Nalgene Cantene (1L: 2.1 oz including redundant lid) or a MSR Hydromedary (2L bag: 2.3 oz). This also reduces my total weight by nearly a kilo, as I don't have to carry the liter of water while it's being treated, as I do with Aqua Mira. The AquaStar doesn't weigh much more than the two full bottles of Aqua Mira (3.2 oz), either. In the winter I use Aqua Mira, since my water is either being boiled, or just melted and sitting overnight for use the next day. No sense trying to keep batteries warm when the chemical taste/smell of AM is totally gone by morning.

David Goodyear
(dmgoody) - MLife

Locale: mid-west
it is all relative on 03/25/2007 16:49:59 MDT Print View

Come on now, you can't seriously be worried about a microliter of untreated water. This guy wasn't:

You have more of a chance of getting sick by not washing you hands when you grab some trail mix, poor personal hygiene and running your immune system down. More crypto cases are due to poor hand washing techniques than drinking tainted water.

Ken Helwig
(kennyhel77) - MLife

Locale: Scotts Valley CA via San Jose, CA
Re: it is all relative on 03/25/2007 17:54:25 MDT Print View

agree with David on the hygiene being the main culprit to backcountry sickness.

Also Douglas is right on with his treatment style. I switched over to my Steripen and have not looked back since. Much, much better than chemicals!!!

Tim Heckel
(ThinAir) - M

Locale: 6237' - Manitou Springs
RE: Steripen Adventurer on 06/07/2007 15:00:53 MDT Print View

I'm pleased to see this review and all the comments, and even more pleased that Miles is monitoring the discussion. Thank you.

I have to agree that the requirement of a wide-mouth container is forcing me to carry heavier and BULKIER containers thus reducing the weight advantage of the Steripen over my filter. Especially since I consider a pre-filter necessary too for use with the Steripen.

Recently I have moved to a ~1.6oz mayonaise jar (about 1L capacity) as an alternative to the ~3.5oz Nalgene bottle.

One contribution I can make regarding an area for improvement has to do with the location and/or brightness of the LED. When in bright light conditions I cannot easily see either the light from the pen nor the teeny LED. This is more than a moderate irritation, as you may imagine, and has probably resulted in multiple treatments of the same water.

Best regards,

Edited by ThinAir on 06/07/2007 15:03:53 MDT.

christian madsen
(sherpachris) - F

Locale: SoCal
Saving weight by eating protozoa on 06/16/2007 11:40:47 MDT Print View

I reduce packweight by drinking all the protozoa and cysts I can! With each 50 gallons of unfiltered, untreated water consumed I gain as much as 1 gram in protein and can reduce my foodweight by an equal amount. I know that chemical and UV treatments don't remove these flavorful tid-bits but they do harm them, cruelly and inhumanly. I prefer my viruses and bacteria in a pure, fresh form. :}

But seriously, I was drawn to this stimulating thread because I'm trying to figure out which device to buy, Aquastar or Steripen. These's no clear comparisson presented here, but I think I'll go with the Aquastar. It's cheaper, can be used as a lamp, comes with a pre-filter and seems easier to operate (screw in and swirl, no need to stir). The drawback is that it requires a wide mouth container to screw into.

Can anyone who has experience with both devices comment about which one they prefer?

I hike in the Sierras alot and normally don't treat water at all. As you might guess, a few drops of "dirty" water on a bottle rim don't cause me much grief. I do use an in-line filter when I'm not happy with the water sources available but UV-C looks like a better way to go.

Sherpa Chris

paul johnson
(pj) - F

Locale: LazyBoy in my Den - miss the forest
Re: Re: Freezing Conditions on 07/23/2007 06:29:06 MDT Print View

>>"It may be very helpful to remember that, apart from the Energiser e2 lithiums, ALL the rest of the lithiums have a water-based electrolyte and, like alkalines, they all freeze up in the cold. They won't work below freezing!"

Roger, that statement has been bugging me for some time. Li reacts violently with water releasing hydrogen and oxygen gas, hence Li fires are self-fueling, IIRC (not a good thing to say the least). I don't believe any Li battery (primary or secondary for that matter) uses water. This is also why water is NOT used to put out a Li fire. I believe, if i have my Classes right, it must be a Class IV fire extinguisher, or a dry chemical (is that the same thing as a Class IV???) extinguisher that is used to put the fire out.

We recently had some Mg shavings in a large dumpster go up at work at ~0300 one morning - i was there to watch 4hrs of fireworks with flames over 100' in the air - looked 100x better than the scene from Raiders of the Lost Ark where the Nazi fuel dump goes up. The fire dept. hit it with water - BIG MISTAKE!!! - WHAT AN EXPLOSION. There after they tested it a few times by spraying a short burst of water up in the air, and letting it sprinkle down on the dumpsters (yes, multiple nearby ones ended up igniting). Yup, still burning!! Only stopped when all of the "fuel" was spent!!

This is why pieces started falling in place in my mind about what i had recalled reading in the Post to which i am replying.

Maybe i'm misunderstanding what you wrote. Please correct me. Many thanks, pj

Edited by pj on 07/23/2007 06:44:03 MDT.

Dondo .

Locale: Colorado Rockies
Welcome back on 07/23/2007 06:33:33 MDT Print View

Nice to have you back, pj.

paul johnson
(pj) - F

Locale: LazyBoy in my Den - miss the forest
Re: Welcome back on 07/23/2007 06:45:20 MDT Print View

Thank you, Dondo. i'm off from work the last couple of weeks temporarily on partial disability. So, when i'm feeling up to it, i'll check in evey once in a while. My trekkin' days, however, are undoubtedly o'er - even after surgery; at least that's what i'm told.

i'm still trying to figure out what to do with my gear - much of it unused or lightly used (some heavily used, but still looks nice - i'm very OCD about keeping my gear in good shape and not abusing it). i have a lot unused simply because, when i find a piece of gear i really like, i buy another one later on before it's no longer manufactured (this has happened to me in the past), and then store it unused.

i'm open to suggestions on how to divest myself of this gear at very low prices, to others who will put them to good use (both unused and very lightly used - i can't seem to mentally part with some of my "old friends" that have served me so well even if i'll never be able to use them again).

Edited by pj on 07/23/2007 06:52:30 MDT.

Dondo .

Locale: Colorado Rockies
Re: Re: Welcome back on 07/23/2007 06:59:30 MDT Print View

I'm sorry to hear that your trekkin' days are over, pj. That must be a tough adjustment.

As far as your gear is concerned, I'm sure the good people here will help you divest. :-D

Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Re: Re: Welcome back on 07/23/2007 08:09:40 MDT Print View

PJ - I too missed your well researched and well written posts. What happened to cause your disability?

Brett .
(Brett1234) - F

Locale: CA
pj, welcome back. on 07/23/2007 09:43:12 MDT Print View

pj, sorry to hear your hiking prognosis. I hope you will be able to advise us with your wise gear research and entertain us with your dry wit for a long time to come. I was a newbie to forums, and of course this site when I started reading your posts, lo many months ago.. now people occasionally thank me for constructing a well-worded post; something I learned from you. This watering hole of gear knowledge has been just a little dry since your previous departure. Welcome back.

kevin davidson
(kdesign) - F

Locale: Mythical State of Jefferson
The return of PJ the Pooh on 07/23/2007 09:49:15 MDT Print View

Hi, PJ. Welcome back! Don't totally be BPL Forum Poster Emeritus. :-)>