Question:
How do you know that the viral infection came from the water? Also, I thought with the .2 pore size it would eliminate viruses? Does the iodine do this instead?
According to my MEC catalogue, the Katadyn removes protozoa and bacteria but not viruses. You need iodine to remove viruses. I’m presently looking at the Pur Voyageur for purification and the Katadyn PF for general filtering. Brian Proud Delburne, Alberta
Response:
From what I have read so far, I have drawn the following conclusions,
please let me know if they are incorrect.
1. The Katadyn pocket filter is the best filter on the market besides
complex machines that can desalinate water.
It is certainly the most expensive field filter. My wife and I got a
viral infection after filtering with a Katadyn PF, so we abandoned it
in favor of iodine-based purifiers, and have never gotten sick again
drinking purified water. So I’d say assertion #1 is wrong. The point
of a filter is to keep you healthy, not to spend a lot of money.
[...]
Okay, we know that a good 0.2 micron filter (Katadyn, MSR, Sweetwater,
whomevers), takes out bacteria and parasites. I have a Katadyn Combi (a
closeout at Great Outdoor Prov. Co. for $115 
which also has a carbon
element (NOT Iodine as shown in the panel 9 chart Bill duplicated here).
Previously I have used Polar Pure (Iodine in solution) for purification.
My understanding is that the high recommended dose of Polar Pure iodine
is based on having to kill parasites and cysts (e.g. Giardia lamblia)
which have higher resistance.
So… if a filter takes out particulates and all the beasties but the
fragile viruses, wouldn’t a much lower dose of iodine be sufficient to
purify post-filtration water? Would anyone like to propose a lower
target iodine concentration for the "kill remaining viruses" post-filter
application? What I’m thinking about is:
"Natural" water – K. Combi – low dose Polar Pure – safe water
instead of
"Natural" water – full dose Polar Pure – K. Combi – safe water
or
"Natural" water – full dose Polar Pure – lots of Tang – :p
Scott "Maybe carrying more white gas really is easier"
[Delete the "NoSPAM-", number, and first "." in mail replies.]
ObRTFM: Panel 9 of the rec.backcountry FAQ is at this URL:
ftp://rtfm.mit.edu/pub/usenet-by-hierarchy/rec/backcountry/[l_m_3_19_98]_Water_filters_&_Giardia_Distilled_Wisdom_(9_28)_XYZ
Another good summary is at http://www.travelhealth.com/purwtr.htm
Katadyn claims here that removing particulates probably also takes
out the viruses http://search.sportsite.com/katadyn/hot_topic.html Posted using Reference.COM http://WWW.Reference.COM FREE Usenet and Mailing list archive, directory and clipping service
Response:
I have a Katadyn Combi (a closeout at Great Outdoor Prov. Co. for $115) which also has a carbon element (NOT Iodine as shown in the panel 9 chart).
This must be a design change, because I could swear the Combi had an iodine element when it was first imported into the US. I have verified via the Web that you are correct. Thanks, I’ll change the chart. My understanding is that the high recommended dose of Polar Pure iodine is based on having to kill parasites and cysts (e.g. Giardia lamblia) which have higher resistance.
Correct. So… if a filter takes out particulates and all the beasties but the fragile viruses, wouldn’t a much lower dose of iodine be sufficient to purify post-filtration water?
Yes. This information used to be on Panel #9, but when a professional microbiologist (Alan Dove) rewrote the FAQ, the information disappeared. Here’s my old blurb: The accepted concentration for iodine disinfection is 8 milligrams per liter, but this is mostly to get rid of protozoan parasites. A good way to reduce overall iodine consumption and minimize that iodine flavor is to filter first, then use a low concentration of iodine to neutralize bacteria and viruses. For this, a concentration of .5 mg/L is deemed adequate, so one capful of PolarPure or one Potable-Aqua tablet should disinfect around 16 liters of lightly filtered water. Various inexpensive ceramic filters with 1 micron pores are fine for removing protozoa. All this came out of military research for WWII — references available upon request. Bill Tuthill
Response:
My two cent’s worth….I have had a Katadyn PF for eight or nine years and have used it a fair amount. It has never given me any problems, is easy to clean in the field. Pumps not quite a quart a minute, and is NOT the easiest thing to hold or pump. Only warning, do not drop or treat roughly, for fear of breaking the ceramic element…In winter, do not let it freeze for the same reason. The ceramic element is expensive to replace, not quite the cost of a new filter. If I had to replace it tomorrow, I’d buy another Katadyn PF. IF you are only an ocassional user, buy the PUR, but if you are going to use it a lot, go ahead and spend the money on the Katadyn. Fight SPAM! Please remove the XXX to reply.
Response:
The table below makes the Sweetwater Walkabout look pretty good, at least for small groups where pumping large quantities isn’t an issue. Any comments? – Hide quoted text — Show quoted text – pore field carbon weight pump L/min pumps filter cost size clean? (oz) force flow per L life (micron) (lbs) rate (gal) Pur Pioneer $ 30 .5 no no 8.4 2 1.0 59 20 SwtWtr Walkabout $ 35 .2 yes yes 8.5 ? .7 ? 100 Pur Hiker $ 55 .3 rinse yes 11.0 8 1.5 48 200 SwtWtr Guardian $ 60 .2 yes yes 11.0 2 1.0 60 200 MSR Miniworks $ 65 .3 yes yes 14.3 8.5 .6 100 1000 1st Need Deluxe $ 70 .1 no lots 15.0 6 1.7 45 100 Pur Voyageur $ 70 .3 + I rinse yes 11.5 12 1.3 53 200 Pur Scout $ 80 .3 + I rinse option 12.0 11 1.0 60 200 SwtWtr Guardian+ $ 80 .2 + I yes yes 15.0 3 .9 60 200,90 MSR Waterworks 2 $125 .2 yes yes 16.6 12 .8 76 1000 Pur Explorer $130 .3 + I self option 24.8 5 1.4 43 400 Katadyn Mini $139 .2 yes no 8.2 13 .5 120 1000 Katadyn Combi $185 .2 + I yes yes 29.2 ? 1.2 50 14000,60 Katadyn PF $295 .2 yes no 22.7 20 .7 82 13000
Department of Psychology web: http:/www.bvu.edu/~ferguson Buena Vista University "The world is older and bigger than we are. This is a hard truth for some folks to swallow." –Edward Abbey
Response:
The table below makes the Sweetwater Walkabout look pretty good, at least for small groups where pumping large quantities isn’t an issue. Any comments?
<<snip Bob, You might also plug in the number of gallons that can be filtered before replacing the filter, and the cost of the replacement filters. Some of the replacements are in the $25 range. Dev Dev Vallencourt Center Designs, Waterbury Center, VT "Just remember that it’s all part of your wilderness experience." – Judy Unick, stepmother extraordinaire
Response:
From what I have read so far, I have drawn the following conclusions, please let me know if they are incorrect. 1. The Katadyn pocket filter is the best filter on the market besides complex machines that can desalinate water. It is certainly the most expensive field filter. My wife and I got a viral infection after filtering with a Katadyn PF, so we abandoned it in favor of iodine-based purifiers, and have never gotten sick again drinking purified water. So I’d say assertion #1 is wrong. The point of a filter is to keep you healthy, not to spend a lot of money.
How do you know that the viral infection came from the water? Also, I thought with the .2 pore size it would eliminate viruses? Does the iodine do this instead? – Hide quoted text — Show quoted text – 2. It provides 15 times the total filtering volume compared to most other filters (15,000 liters). The Katadyn Combi is also durable, as are MSR’s MiniWorks or WaterWorks2 ceramic filters, which I believe are underrated at 1000 gallons (3785 L). 3. It is harder to pump than most filters. Yes, see comparison chart below. It is the hardest to pump, although the Katadyn Mini is the slowest to pump. Besides price (and in the long run it looks like the Katadyn will be cheaper anyway), why would I purchase any other filter? There is a good reason for buying every filter on this list. All are quality products with tradeoffs. Decide what you want! Bill Tuthill [Sources: REI Product Information Guide on Water Filters, Fall 1997 plus Campmor, SweetWater, and MSR Web pages ] pore field carbon weight pump L/min pumps filter cost size clean? (oz) force flow per L life (micron) (lbs) rate (gal) Pur Pioneer $ 30 .5 no no 8.4 2 1.0 59 20 SwtWtr Walkabout $ 35 .2 yes yes 8.5 ? .7 ? 100 Pur Hiker $ 55 .3 rinse yes 11.0 8 1.5 48 200 SwtWtr Guardian $ 60 .2 yes yes 11.0 2 1.0 60 200 MSR Miniworks $ 65 .3 yes yes 14.3 8.5 .6 100 1000 1st Need Deluxe $ 70 .1 no lots 15.0 6 1.7 45 100 Pur Voyageur $ 70 .3 + I rinse yes 11.5 12 1.3 53 200 Pur Scout $ 80 .3 + I rinse option 12.0 11 1.0 60 200 SwtWtr Guardian+ $ 80 .2 + I yes yes 15.0 3 .9 60 200,90 MSR Waterworks 2 $125 .2 yes yes 16.6 12 .8 76 1000 Pur Explorer $130 .3 + I self option 24.8 5 1.4 43 400 Katadyn Mini $139 .2 yes no 8.2 13 .5 120 1000 Katadyn Combi $185 .2 + I yes yes 29.2 ? 1.2 50 14000,60 Katadyn PF $295 .2 yes no 22.7 20 .7 82 13000 Notes: cost reflects lower of Campmor or REI retail price pore size must be < .3 micron to filter out small bacteria activated carbon can reduce toxic chemicals and heavy metals pumping force can increase considerably as filter clogs output rate can decrease substantially as filter clogs capacity as rated by manufacturer, might not be accurate with silty water First Need clogs more rapidly than Pur Hiker models labeled "+I" use iodine to neutralize viruses and bacteria MSR filters do not include cost of handy stainless steel screen Katadyn Mini requires frequent cleaning because of small size under filter life, numbers after comma indicate iodine longevity only Explorer is self cleaning– others require disassembly
Response:
I’ve owned two Katadyns over the past 10 years, and recently sold my last one and replaced it with a PUR. Why? Mainly because, ergonomically, the Katadyn is the hardest filter to pump that I’ve ever used. When it’s crystal-clean it’s not too bad to pump, but when it get even a little bit dirty watch out! (And don’t even start me on the idiotic handle design.) Also, the Katadyn will not filter viruses like many of the PUR models will. The Katadyn is great if you use it a lot, and it will definitely end up being cheaper in the long run. It’s also easy to repair and clean in the field. It’s definitely quality-made, too (and you pay for it). I’ve used most filter brands over the past 15 years or so, including selling most of them in an outdoor store that I managed. I’d recommend a PUR or MSR for the average weekend camper (with the occasional long trip thrown in), and a Katadyn for larger groups or longer trips. My lowly opinion, of course. Brian Wasson
Response:
Besides price (and in the long run it looks like the Katadyn will be cheaper anyway), why would I purchase any other filter?
I don’t find mine hard to pump at all. When you factor in the time to field maintain various filters, the Katadyn PF filters more water in the same amount of time (not based on any study or official numbers – just observations and personal experience). I’m now on my third and last filter, a Katadyn PF. I’ve suffered from dehydration once and watched a friend experience Giardia. Therefore I take water filtering and consumption very seriously. You will not regret this purchase. Just stay away from the Mini version. It’s slow, clogs quickly and takes many many little pumps to get a little sip of water. Mike — Expedition Leader, Inc. http://www.expedition-leader.com Makers of the Canadian Shield 4-season composite camping mattress. Online distributors of technical outdoor apparel, canoe packs and accessories. My personal backcountry journal – http://www.expedition-leader.com/journal
Response:
From what I have read so far, I have drawn the following conclusions, please let me know if they are incorrect. 1. The Katadyn pocket filter is the best filter on the market besides complex machines that can desalinate water. 2. It provides 15 times the total filtering volume compared to most other filters (15,000 liters). 3. It is harder to pump than most filters. Besides price (and in the long run it looks like the Katadyn will be cheaper anyway), why would I purchase any other filter?
Response:
From what I have read so far, I have drawn the following conclusions, please let me know if they are incorrect. 1. The Katadyn pocket filter is the best filter on the market
You are right. David Avigdor Licensed Adirondack Guide
Response:
From what I have read so far, I have drawn the following conclusions, please let me know if they are incorrect. 1. The Katadyn pocket filter is the best filter on the market besides complex machines that can desalinate water.
It is certainly the most expensive field filter. My wife and I got a viral infection after filtering with a Katadyn PF, so we abandoned it in favor of iodine-based purifiers, and have never gotten sick again drinking purified water. So I’d say assertion #1 is wrong. The point of a filter is to keep you healthy, not to spend a lot of money. 2. It provides 15 times the total filtering volume compared to most other filters (15,000 liters).
The Katadyn Combi is also durable, as are MSR’s MiniWorks or WaterWorks2 ceramic filters, which I believe are underrated at 1000 gallons (3785 L). 3. It is harder to pump than most filters.
Yes, see comparison chart below. It is the hardest to pump, although the Katadyn Mini is the slowest to pump. Besides price (and in the long run it looks like the Katadyn will be cheaper anyway), why would I purchase any other filter?
There is a good reason for buying every filter on this list. All are quality products with tradeoffs. Decide what you want! Bill Tuthill [Sources: REI Product Information Guide on Water Filters, Fall 1997 plus Campmor, SweetWater, and MSR Web pages ] pore field carbon weight pump L/min pumps filter cost size clean? (oz) force flow per L life (micron) (lbs) rate (gal) Pur Pioneer $ 30 .5 no no 8.4 2 1.0 59 20 SwtWtr Walkabout $ 35 .2 yes yes 8.5 ? .7 ? 100 Pur Hiker $ 55 .3 rinse yes 11.0 8 1.5 48 200 SwtWtr Guardian $ 60 .2 yes yes 11.0 2 1.0 60 200 MSR Miniworks $ 65 .3 yes yes 14.3 8.5 .6 100 1000 1st Need Deluxe $ 70 .1 no lots 15.0 6 1.7 45 100 Pur Voyageur $ 70 .3 + I rinse yes 11.5 12 1.3 53 200 Pur Scout $ 80 .3 + I rinse option 12.0 11 1.0 60 200 SwtWtr Guardian+ $ 80 .2 + I yes yes 15.0 3 .9 60 200,90 MSR Waterworks 2 $125 .2 yes yes 16.6 12 .8 76 1000 Pur Explorer $130 .3 + I self option 24.8 5 1.4 43 400 Katadyn Mini $139 .2 yes no 8.2 13 .5 120 1000 Katadyn Combi $185 .2 + I yes yes 29.2 ? 1.2 50 14000,60 Katadyn PF $295 .2 yes no 22.7 20 .7 82 13000 Notes: cost reflects lower of Campmor or REI retail price pore size must be < .3 micron to filter out small bacteria activated carbon can reduce toxic chemicals and heavy metals pumping force can increase considerably as filter clogs output rate can decrease substantially as filter clogs capacity as rated by manufacturer, might not be accurate with silty water First Need clogs more rapidly than Pur Hiker models labeled "+I" use iodine to neutralize viruses and bacteria MSR filters do not include cost of handy stainless steel screen Katadyn Mini requires frequent cleaning because of small size under filter life, numbers after comma indicate iodine longevity only Explorer is self cleaning– others require disassembly
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