Wednesday, 17 July 2013

Steri Pen

          I`ve been aware of these for quite a while now but never really had the desire to buy one, until a couple of months ago when Trail magazine offered a free one when people took out a subscription to the magazine which at £50 for 13 editions worked out a lot cheaper than the £67 asked for just the steri-pen itself, even though I do prefer reading TGO magazine I took out the subscription and began the long wait for the device to arrive. How do these devices compare to other methods of water purification though?

          More traditional forms of water purification include chlorine, chlorine dioxide and for those of us lucky enough to remember it iodine, as well as various filters and while these worked they did have they`re various downsides, chlorine doesn`t kill off all the bacteria present in water and leaves a nasty taste behind, unless you use neutralising tablets, iodine kills off more but not only leaves a nasty taste behind but has a tendency to stain everything it touches which then leaves you questioning what your guts look like, although ironically you do get used to the taste and notice it when its gone, they are however easier to get hold off, with the exception of iodine, don't require batteries to work, take up much less space, weigh less and can purify more than one litre at once, although this does have another downside in that there is a period of time to wait for the chemicals to work, anything from half an hour to three hours depending on the chemical and the amount of water that's being purified (add extra time for neutralising tablets).

          Another method of purifying water is through the use of filters such as the Katadyn filters, these work by filtering bacteria from water and without bacteria viruses can not survive, depending on which one you buy will depend on what you get from the filter, some of these filter water quicker but at the cost of having less life, others can filter a lot more water (up to 50,000 litres) but are heavier, more complicated to use and require more maintenance and others are smaller and lighter but take longer to work, the major advantages of filters however is the ability to fit any bottle type, the far greater capacity to purify water and the total absence of electrical power, the major downside is the relative cost of the unit, these filters range in price from £115 to £300 with spare filters and silicone gel sold separately.

          The Steri-pen uses a pre filter to extract dirt particles and then ultraviolet light to break down the DNA structure of the bacteria within water and takes a surprisingly short time to do so, this major advantage means that there is a very short waiting time between collecting water and being able to drink, there is no calculating chemical to volume ratio involved and no aftertaste. it is however limited to the amount of water it can purify, generally one litre at a time, this is a small price to pay though considering how quickly that one litre is done. one other disadvantage to the Steri-pen is that it runs off batteries which are usually 4x AA (which in personal terms means I now have to carry two types of spare battery rather than just AAA) but to make matters a little more complicated Steri-pens work best with Nickel-Metal-hydride (NiMH) batteries, which are naturally more expensive but on the plus side are generally rechargeable. side note; I picked up a rechargeable unit and 4 batteries at my local supermarket for £16 (yeah I know it makes it the same price as buying from a shop, but I still would have needed to buy the batteries anyway), the biggest disadvantage to the Steri-pen however is purely psychological, it may just be me but because I can`t see anything changing or fizzing or taste anything after drinking I`m constantly thinking "has it actually worked?" of course Steri-pens wouldn't be on the market if they didn't work but there is something reassuring about seeing water change colour as iodine works, further use of this new piece of equipment is really going to be needed before I can trust it fully.
          As a further comparison Camelbak also make there own version of a ultraviolet light bottle the advantage of which it has an in built rechargeable battery and a countdown timer but on the downside cannot be used in any other bottle.
          With any overseas expedition or extended expedition in the UK the need for clean water becomes paramount and all the methods mentioned above are all effective the one you choose of course is entirely yours.

As with all outdoor equipment personal preference is key to any decision you make.

Follow the link below to go to the Lone Wolf Mobile Bushcraft website.

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