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I use a first need water purifier. It weighs around 18 ounces but filters down to .01 microns. It claims to take everything (including viruses) out of the water and I haven't had a problem yet. It costs around 80 bucks. I have also used iodine tablets and bleach, personally I like the purifiers (not just filters) better.

I would like to upgrade to a unit thats lighter and has a higher flow rate. Of course I want to retain the purifying aspect of the unit, any suggestions?

MSR Miniworks EX filter is what I use. It can produce a liter of water in about a minute and weighs 14 oz.

I use the Pre-Mac MWP. It's a british military design. It's lightweight, kills everything including viruses and has a flow rate of three minutes per liter.
It has been tested and approved by the London School of Hygiene and Tropical Medicine. It is also safe to use in cold conditions. The down side is that it's an import which means more $$.
Each cartridge will treat about 250 liters of water. I went ahead and purchased an extra set of cartridges so I wouldn't have to spend extra money on shipping. If I'm hiking along a creek or river I'll use good old 2% tincture of Iodine, five drops to the quart or liter.
Check out this website:
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This is where I purchased mine:
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Joe and Sara
"That which does not kill us makes us stronger" F.N.

I too use the First Need, its heavy and not too fast but I've filtered some nasty water with it and glad to be able to rely on it with no problem (Don't get downstream of those cow patties).

matt gilbert wrote:...filters down to .01 microns. It claims to take everything (including viruses) out of the water...

Don't believe everything you read when looking at the advertising a filter publishes. .01 microns is enough to filter out any type of bacteria or protazoa including the notoriously difficult cryptosporidia (forgive any lapses in spelling - I'm going off memory and not doing my typical double-check of facts).

Viruses are another thing entirely. If you had a filter that could eliminate viruses through filter size, you would not be able to force water through it. For a while some manufacturers experimented with iodine shock filters on their pumps. The theory was that the iodine would "shock" the water enough to kill the viruses. Lab results indicated it worked - field results said otherwise. I am unaware of any manugacturer that is still making an iodine shock filter.

Any normal fiberglass or ceramic filter is simply incapable of filtering out viruses - being molecular in size, they simply cannot be captured by any normal filtration process. To eliminate them you must use a chemical process (iodine or chlorine will work).

Fortunately viruses in water are normally only a result of human waste infecting a water supply, so the occasions it is necessary are thankbully rare.

This topic has been discussed before, with a lot of really good information. Check it out here

MSR Miniworks EX filter I think is about the best thing going for a few reasons.. the bigest is you can clean the filter in the field. So its not as fragile as most of the filters that are made of paper.

this is really important to me because im a little parinoid.. remember? some water is really clean beforyou filter it. sometimes tho it may not be and thats where this filter is better bucause you can take it out and clean it on the spot. the last thing you want when you need water is a cloged filter. that can happen really fast when it rains, the creeks and rivers here turn brown fast.

go to rei and have a look at them before you buy one. you will be glad you did.

I also use the MSR AND chemical treatment. It's just the only way to get the viruses killed as well.

olesma wrote:Don't believe everything you read when looking at the advertising a filter publishes.

This one has FDA approval to back the claims that it takes viruses out. Its not a ceramic or other traditional filter they refer to it as a matrix of some kind, its actually osmosis as best as I can figure. I'm pretty confident of the FDA approval , the first need I have is the civilian edition of the same one they issue to NATO troops. They guarantee you can drink safely from the dirtiest rivers in africa. I'm not saying they have my full confidence but I've drank from some pretty foul water sources and never had a problem. Its the weight of the thing that gets me. I want to find a lighter one but I don't want to have to use chemicals before I pump, it just seems to defeat the purpose. The other thing I like about the filter is its completley cleanable in the field. All you have to do is turn the cartridge upside down and pump clean water through it. Theoretically one filter is good for the life of the pump. The only thing that can damage it is a fall in which the filter cartridge gets the brunt of the force.

General Ecology which is the maker of First Need also makes a smaller version called the Microlite. It weighs in at 7 onces. The drawback is they don't guarantee the removal of all bacteria, viruses, etc. without the addition of tablets. Their website is pretty informative but you'll have to search for it yourself since I don't know it offhand. I use the First Need Purifier myself and say it's awkward to use by oneself but it's nice to be able to clean it in the field which also is awkward. I researched purifiers before buying and found it was the only one out there at the time and might still be that's FDA approved.

matt gilbert wrote:I use a first need water purifier. It weighs around 18 ounces but filters down to .01 microns. It claims to take everything (including viruses) out of the water and I haven't had a problem yet. It costs around 80 bucks. I have also used iodine tablets and bleach, personally I like the purifiers (not just filters) better.

I would like to upgrade to a unit thats lighter and has a higher flow rate. Of course I want to retain the purifying aspect of the unit, any suggestions?

I use MSR Miniworks EX filter. Light, and easy to clean in the field.

Another vote for the MSR Miniworks Ex! I wouldn't buy anything else. Viruses are not generally a problem in North America - but if you're worried, you can always treat with iodine first, then filter out the nasty iodine taste.

Please correct me if I'm wrong, but the saving grace with viruses is that the don't last long outside of the host organism,in other words, they don't do well in a stream of water.

i prefer to use chemicals in the water. I have a very inexpensive 1 micron filter if the water is nasty lookin. i carry a small bottle of chlorine just a drop per liter works well and doesn't leave a bad taste. i previously used iodine tablets....yuck makes the water taste like it came from a hose.

Aqua Mira is what I use.
For extremely cloudy water I filter through some fleece before treatment - try it, it works great.

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By Ryan N. Jordan, Ph.D.

I've had the opportunity to review the scientific validity of chlorine dioxide chemical treatment, including McNett Aqua Mira ("AquaMira") as a means of portable water treatment for several years. Our research group at Montana State University has investigated its efficacy against pathogenic bacteria, and primarily, bacteria attached to silt and soil particles in the biofilm mode of growth ("biofilms"), which are notoriously resistant to killing by traditional germicides such as chlorine (bleach) and iodine. In short, chlorine dioxide's efficacy against biofilm bacteria (and the protozooan cysts and viruses entrapped in bacterial biofilms) can be attributed to its ability to penetrate the depths of the biofilm, a characteristic that cannot be matched by iodine or chlorine. Consider that the majority (some say 99.9%+) of bacteria in natural stream and lake waters (let alone stock tanks) exist in the biofilm mode of growth where microorganisms are associated with suspended particles or agglomerated with each other, then a germicide that can effectively penetrate these "slime layers" is going to have a higher probability of neutralizing the pathogenicity of these bacteria. Also consider that an increasing number of waterborne intestinal illnesses are resulting from bacteria (despite the increasing hype about viruses and protozoa) such as Enterococci (common in areas where stock animals are allowed). After reviewing virtually ever water treatment technology on the market (both chemical and physical), I have settled on Aqua Mira (AquaMira) as my backcountry treatment of choice. I have used Aqua Mira (AquaMira) alone on clear mountain streams, mucky pond water, stock tanks, ranchland / rangeland / riparian waters (including irrigation ditches), and international waters known to be contaminated with amoebic pathogens and other forms of dysentery. For more contaminated or suspect waters, I do recommend doubling the dose and/or the contact time, but for most U.S. backcountry locations in the mountain west, the standard dose and contact time is usually sufficient (with high stock use areas being the exception).

Since posting this topic I have had a pretty drastic change of heart about the filter/purifier I use. After reading a little bit about filters vs purifiers, I completely gave up on the idea of needed to purify water. Viruses in water are rare (especially in the US), and purifiers are too heavy or take too long (four hours for crypto with chemicals).

I now use the MSR sweetwater. I chose this unit over the miniworks for two reasons. First and foremost was the weight. The second was the durability of the cartridge in the MW. The ceramic filter (while more cleanable) is very fragile. I have seen them break after dropping the filter from chest hieght onto a carpeted floor. In my opinion the greater flow rate on the MW was negligible (an extra .1 liters per minute).

I still think the MW is a good unit, it just doesn't quite suit my needs. Overall I think that MSR makes the best filters if only because they are all field cleanable.

I used the hiker pur for years. I now have new Katahdyn. I like it a bit better, it's easier to pump and a bit lighter. I used to use liquid bleach--two drops per quart in clear water, shake, let sit 1/2 hour. Dirty looking water, 3 to 4 drops, wait 1/2 hour, etc. This works very well in USA for those on a limited budget. I can't speak for foreign travel, however.

In response to matt gilbert's reply:

Matt,

I concur with your opinion on the MSR Sweetwater. I bought this filter two years ago and have filtered some nasty looking water with it....never got sick.

It's fast and efficient.

matt gilbert wrote:Since posting this topic I have had a pretty drastic change of heart about the filter/purifier I use. After reading a little bit about filters vs purifiers, I completely gave up on the idea of needed to purify water. Viruses in water are rare (especially in the US), and purifiers are too heavy or take too long (four hours for crypto with chemicals).

I now use the MSR sweetwater. I chose this unit over the miniworks for two reasons. First and foremost was the weight. The second was the durability of the cartridge in the MW. The ceramic filter (while more cleanable) is very fragile. I have seen them break after dropping the filter from chest hieght onto a carpeted floor. In my opinion the greater flow rate on the MW was negligible (an extra .1 liters per minute).

I still think the MW is a good unit, it just doesn't quite suit my needs. Overall I think that MSR makes the best filters if only because they are all field cleanable.

Matt,
Someone was listening....

http://www.trailspace.com/news/2006/08/ ... vario.html

Katadyn Micropur - Almost no weight as long as you don't mind occasionally drinking water with some dirt in it. Doesn't taste that horrible, either.

I love my MSR Mini-Works EX, I wouldn't even consider switching right now. No problems in the muddy Paria, Colorado River, Little Colorado river, field maintainable. I love it!