Re: [BackpackGearTest] Digest Number 93
- Thanks, Doc, for a perfect answer.Jerry----- Original Message -----From: Orange BugSent: Saturday, January 13, 2001 2:54 PMSubject: Re: [BackpackGearTest] Digest Number 93Jack, you are making a small mistake about what a filter is, and what a
water purifier is. To use your PUR example, their "Voyager" purifier
adds iodine to water after it goes through a filter cartridge. The
filter cartridge without the iodine is sold as the Hiker filter. In
general, the need for iodine after a filter is to kill virus particles.
In North America, that is rarely necessary.
Filters and water purifiers are sold as a health related item, with
claims of ability to reduce cysts, eggs and bacteria from human
consumption. Hence, they have to have proof of these claims from FDA.
The bacteriology labwork is done long before customer trails are
These companies also have to keep their product liability
lawyers/insurers happy. PUR had a problem with part of their purifier
last year, apparently removing the iodine taste before the iodine had
much chance to work.
Filters are popular for the quick access to water from a questionable
source. There is a cost in the price of the equipment and the weight.
The newer inline filters have very low weight, but have to be replaced
more frequently than other filters. There are also fewer breakable
parts. They can clog from dirt and silt, as well as break from
freezing. A safewater Anywhere inline filter usually costs as much as a
new Hiker replacement filter cartridge, but is good for about 1/4 as
much water treatment (I think from memory). It also weighs less than a
quarter of the Hiker.
Other choices include boiling - at the cost of time and weight for
extra fuel. Iodine, chlorine and other bleaches work with very little
weight cost, but take a substantial amount of time to work to kill the
toughest paracites - such as giardia. A filter in a purification system
gets the larger particles, allowing iodine to rapidly kill the virus
(usually less than five minutes). Certainly, you can drink with limited
risk of getting a water borne infection or paracite. However, when you
do get ill, the cost of illness and recovery may be much higher than
the most expensive water treatment option.
The company needs our input on how the filter works in the real world,
especially to avoid poor instructions, breakage or other problem. In
the initial test for this list, there was much preoccupation with
studying how the filter worked, including "tests" that were probably
doomed - such as complaints that food dye passed through the filters.
The cheapest, lightest and easiest water treatment will probably remain
iodine. I don't like having to guess dosage and time based on water
temperature. I carry Polar Pure as my backup water treatment, and
sanitizer for wounds. My primary treatment is the Safewater Anywhere
inline with my Platypus bags.
--- BackpackGearTest@egroups.com wrote:
> Date: Sat, 13 Jan 2001 11:25:25 -0500
> From: "Jack Voss" <vossj@...>
> Subject: Re: New test
> On a serious note, I've always been impressed with the Pur water
> treatment units. They not only filter out bud stuff, they use iodine
> and activated charcoal to kill the left overs. It sounds to this
> layman as thought the Pur units go one step further. If I'm going to
> make a mistake on drinking water, I'd hope to make it in the
> direction of too much safety. I already enjoyed the experience of
> bad water in Viet Nam. Not fun.
> I'm looking forward to being involved in this round of tests.
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