*Water Filters and Purifiers*
By Tailgunner

Water Filters and Purifiers

Water is important to our bodies, we don’t last long without it, and though it may be rather plentiful, most of the water we find needs to be treated or filtered before we can safely drink it. I have been using the Iodine tablets as issued to the military for years, though they work fine for most water purification chores, the water can still look murky and taste lousy. Iodine is very effective against bacteria and viruses, but not against cryptosporidia. Also, pregnant women and small children shouldn't injest a lot of Iodine. Iodine imparts a slight odor and taste (which can be removed by taste-neutralizer tablets) to the water and requires a long contact time in cold or murky water. Thinking that there had to be a better way I embarked upon a quest to find a good water filter or purifier. As I looked at this subject more and more it became somewhat confusing. There were many models available and they all touted themselves as the best deal. I spent some time searching the internet for reviews on water filter/purifiers and came up with the general consensus that almost all of the ones I was looking at on the market had mostly good and some bad experiences. That didn’t help. So I looked to see what the specs were for the ones I considered for purchase and came up with the following chart for Water Filters:

And for Water Purifiers: (purifiers are rated to kill viruses also)

On a recent river float trip I used both PUR Hiker and MSR MiniWorks filters. Because I wanted to find out for myself how well they worked. The long and short answer was, they both worked great! They were fairly easy to pump and I had my water bottle filled up in short order, the PUR was a bit faster but usually took two people to fill a quart canteen, because of the hoses involved.

Notes from use:

Katadyn Pocket Filter: I used this filter, or one like it, years ago, it was hard to pump and was very slow to fill a canteen. This along with its high cost put me off from buying a filter for my water purification. At the time the iodine pills seemed fine to me especially when cost was compared. However, the Katadyn was easily cleaned in the field and with its silver content (in the filter element) it prevented bacteria growth between trips. It filters the water with a ceramic/silver filter element down to .2 micron, so some of the smaller viruses still could be a problem (the Red Cross must be comfortable with it because they had selected Katadyn products for water filtration when traveling in 3^rd world countries). It is rated to filter approximately 13000 gallons of water before needing a filter replacement. This in itself may make the Katadyn the most cost effective over a long term use. I included the data on the Katadyn Combi filter because Katadyn improved their basic design to make it easier to use and get away from the complaints voiced by many users..

MSR MiniWorks: I am very pleased with the way the MSR equipment is designed to be user maintained. They produce a repair kit that I included in the storage bag. Spare filters are less than $30.00 and last a long time. The filter unit includes the filter, a storage bag, a green scouring pad to clean the ceramic filter and a gauge used in determining when the filter needs replacing. It is designed so that you can screw a Nalgene wide mouth bottle to the bottom and pump away without trying to juggle the pump and fill a water bottle at the same time. Did I mention easy to maintain, you can use chapstick to lube the pump (course they include a tube of silicone grease with the filter and in the repair kit). If I were worried about really small viruses in the water I would try to treat the water with Iodine tabs first let it set the 20 minutes then filter normally, or boil the filtered product for 2 minutes at a rolling boil (according to the CDC only one minute is enough at a rolling boil regardless of elevation). The filter is designed to remove most of the Iodine flavor and any viruses that attach themselves to a larger particle. It was difficult to find a listed filter life expectancy, however, it uses a ceramic filter similar to the Katadyn so I think it should produce in the thousands of gallons also before needing replacement. The Waterworks II filter uses the same filter element and most parts, but it includes a .2 micron membrane filter as a final stage in filtration.  One note is that after you return from a trip, you should clean your filter element by rinsing it off in cool running tap water with light scrubbing if needed, or boil it in clean water and set it aside to air dry for 2 or 3 days (to prevent algae and bacteria growth in the filter).

PUR Hiker/Voyager: This one was the easiest to pump and quickest to fill my water bottle requiring less than a minute of steady pumping. The PUR filters/purifiers use a glass fiber filter to remove particles down to .3 micron, easily filtering out giardia and cryptosporidia and bacteria. If you were worried about viruses in the water you might want to change the filter to the Iodine resin impregnated matrix found in the Voyager. I noted a very slight iodine smell and flavor when using this filter on the second day. It seems that I left a little water in the filter that apparently picked up some Iodine that was then pumped into my water bottle on the second and subsequent days. These filter elements have a rated capacity of approximately 200 gallons of water (depending on clarity/turbidity). Spare filter elements are between $25 and $40 depending on whether you want just the filter or filter with iodine. After a trip this filter element should also be removed and rinsed off with cool tap water and set aside to fully air dry for 2-3 days before storage in preparation for the next trip (to prevent algae growth in the primary filter).

Sweetwater Guardian: I could not find one of these to try. It had the most negative reports on various internet sites, plus I could not find one in the local stores here in Alaska, to get hands on time. I have included it because my research indicated it was in the ball park. Anyone have one and can report on its performance?

One of the first questions you need to ask when thinking of getting a filter/purifier is "what level of filtration or purification do I need to worry about". In forests and waterways of the U.S. and the majority of the world most water is reportedly contaminated with protozoans such as giardia and cryptosporidia, and of course bacteria. With a pore diameter of 0.2 or 0.3 micron the filters prevent even the smallest bacteria that cause dangerous illnesses including typhoid, dysentery, cholera, e.Coli, collibacillosis, amoebic dysentery and bilharciosis from passing through. Unless you have a real concern about viruses in the water, such as may exist in many third world countries, a filter would work just fine. Most of these filters also include an activated charcoal filter to take out many chemicals including hydrocarbons, iodine, pesticides, metals and other disagreeable things. The activated charcoal attaches at a molecular level to most chemicals and metals and traps them in the filter element.

The PUR Voyger and Sweet Water Guardian Plus are rated to take out the viruses too by using an Iodine resin matrix in the filter element, it would seem that the contact time would be somewhat limited in the filter itself, but they seem to impart a small amount of iodine to the water. Both of these purifiers put a carbon filter after the iodine matrix to remove most of the iodine taste and color.

My choice for the best all round filter was the MSR MiniWorks. It has a relatively low cost and the filter element lasts a good long time before needing replacement and it is easy to work on should the need arise. I have put one in my BOB and have put the PUR in my regular camping kit. I think I will try to get one of the MiniWorks filters for each of my kids also for their BOBs.  These filters are great tools and are my primary method of filtering questionable water, but I still include iodine tabs in my BOB, and in my belt survival kit just in case.

Tailgunner

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