staehpj1

I have not found taking a filter to be worthwhile on most US tours. That said there are places where it makes sense. On the Sierra Cascades route it was well worth it. It was very hot out but there were lots of ice cold mountain streams. Freshly filtered ice cold water was nice to have.

On the ST anywhere that there wasn't frequently available tap water there also was no surface water to filter.

On the TA I found little enough use for it that I mailed it home.

The new filters like the Sawyer mini or the Squeeze are light enough (about 2 and 3 ounces respectively?) that taking them along is more tempting. I have used both a Squeeze and a Mini a lot for backpacking and also on The SC and found them very trouble free. After long storage it sounds like a good idea to check them before a trip to be sure they are flowing.

The problems with the bags can be avoided if you handle them with care and carry a spare. I think folks squeeze them too hard. I have used them a lot and never burst a bag. I either squeeze gently or if not in a hurry hang them up and let gravity do the work

robow

+1 I always keep a few of these in my first aid bag "just in case" on any tour. Take up no space and weigh nothing.

On my canoeing adventures into the northern wilderness, I always carry my Katadyne Hiker water filtering system which sees daily use but much too heavy and bulky to consider for my touring.

hilltowner

Aqua Mira is entirely different from iodine. It is a two-part system that produces chlorine dioxide. However, it is not the same as sodium hypochlorite which is the main ingredient in bleach and which is also used to purify water, imparting that "chlorine" taste. Aqua Mira treated water has no residual taste as is the case with chlorine and iodine based systems. If you read their literature they only claim to purify "potable" drinking water which is a bit disconcerting. I'm not sure exactly why they aren't claiming to disinfect water but one study that was done seems to support the idea that the treatment is effective against a wide-range of water borne pathogens and is better than iodine and filters at eliminating the risk of ingesting something bad. See here: Aqua Mira FAQs and here: Efficacy of Water Treatments study I have used it successfully (at least I haven't yet gotten any intestinal parasites) for the last 10 years backpacking and touring (and drinking from streams and lakes in Maine, Labrador, Quebec, and Ontario while doing so).

DeadGrandpa

+1. I used the Squeeze, backpacking, as a gravity fed inline filter from a 3L collapsible canteen, and only had problem with reduced flow when the filter needed to be backwashed with the supplied syringe. One caution: if you are filtering water downstream from farm fields, you might want to upgrade to a heavier MSR mini or Katadyn pump which has a carbon filter to remove toxic chemicals. Melted snow at mountain top, no problem; stream with run off from pastures or row crops, sicky-poo.

cyccommute 

Yes, it is. But you have to love marketing. The MSDS for Part A says that the solution contains "stabilized chlorine dioxide" which is kind of a weasely way of a water solution of a salt. I know how to make chlorine dioxide but I'd rather not tell people how to do it since chlorine dioxide can be quite hazardous in high concentrations and it is very easy to make.

Chlorine dioxide also imparts a "chlorine" taste. Gaseous chlorine has been replaced in most places to treat drinking water but it can still leave that "chlorine" taste. I wouldn't use sodium hyprochlorite...aka household bleach...to sanitize water.

There is a reason that their literature says that it can only be used for "purifying" (really sanitizing) potable water. Chlorine dioxide is an aggressive, but indiscriminate, oxidant. It will oxidize important parts of organisms which kill them but if there is plant material present in the water as could occur if you have unfiltered stream water, the chlorine dioxide will also oxidize parts of that plant material as well. Most of the oxidant would be wasted on the plants, which don't need sterilization, and not on the organism which can cause you harm.

For municipal water treatment, chlorine dioxide is used as a polishing step to kill anything that gets through the filtration system. It's too expensive to use upstream of the filters. The same is true for backcountry uses. The Aqua Mira would be useful for places where the water quality is doubtful but you would still need to remove most of the organic material before use...and that means filtering the water beforehand. Since the filter removes most of the organisms to begin with, I'm not sure the use of the chemical treatment isn't just a bit of OCD treatment.

AAAAAAARRRRRGGGGGGGGHHHHH!!!!!! Marketers! Damned marketers! Stupid, damned marketers! Comments like these drive chemist crazy!

Aquamira isn't a "breakthrough" in technology nor does it use "stabilized chlorine dioxide". It's a relatively simple chemical reaction that has been know for a very long time. But the comment that really, really, really chaps my hide is this absolutely stupid comment

Yes, chlorine gas and gaseous chlorine dioxide are two different chemicals but both have the element "chlorine" in them. Chlorine dioxide will decompose...quite violently and unexpectedly in a slow speed explosion front called a "puff"...into chlorine gas and water in the right conditions. You can't even compress chlorine dioxide into a gas cylinder because that makes it even more unstable.

As for this claim

Chlorine dioxide can form many of the same potentially harmful by-products. It is an oxidant that contains chlorine which can react with organic molecules to form halogenated compounds. It's mostly safe in low concentrations but the chemistry is still much the same as other forms of chlorine salts and compounds.

cyccommute 

As I've said above, the lack of flow for the filter was a very unwelcome and unexpected surprise. If I had known about the problem before hand, I could have addressed it but when you are in the middle of nowhere without the ability to address the problem and almost incapable of getting water, shoulda coulda woulda doesn't help. I've used other filters and never had any kind of storage issues. Sawyer could have made the suggestion that you might want to treat your filter before heading out after storage.

The product is nice and light but if it fails, it's not of any use no matter how light it is. I simply can't suggest to anyone that they depend on this filter.

Utilizing melted snow would depend on the time of year. Our snow gets a distinct "pink" color to it from algae in the early summer and probably wouldn't be the best to ingest. We also have a lot of problems in Colorado with mine drainage that contain heavy metals and which won't be fixed with activated carbon filters.

As for drinking straight from any stream I avoid it. Even here in Colorado, beaver poop in streams and, to quote the great W.C. Fields: "Don't drink the water, son. Fish fornicate in it."

carfart

I've used a Katadyn squeeze bottle filter which is a lot of effort but better than nothing. However, I'm now aware of heavy metal contamination in just about all the water sources, including municipal, in my area. Given the option I would prefer to take something that can filter out heavy metals, especially when touring areas with a long history of mining, heavy industry, factory farming, or coal-fired power plants. The pickings appear to be really slim there. The Waterman Mini is just about the only thing I can find, and that's mostly only available in Australia. Something like this looks useful: New portable water filter uses nanoparticles to remove biological and heavy metal pollutants : TreeHugger. Hopefully that kind of thing will make it to production.

hilltowner

Cycocommute,

Thanks for the critique of the A.M. marketing propaganda. I'm very grateful you cut through the b.s. Any comments on the study that I linked to?

(Phil)ltowner

veganbikes

Since most of my touring is done on roads and near enough to decent water I am not super worried. Though if I were to get a filter it would either be a Platypus Gravity Works filter (for larger groups or more water) or a Katadyn Hiker pro. I have carried tablets for extreme extreme emergencies but I would try to avoid using them. I would also avoid some of the lightweight or less durable designs, stick with good proven technology and companies that put out a quality product and stand behind it.

The C&O canal water isn't the greatest but the iodine taste is very very weak and I haven't gotten sick but then again I try to build up some immunity and I happily drink tap water in most places.

Check your equipment well before your tour and store it properly. You never want to find out something just isn't cutting the mustard while out(unless it is a mustard cutter, then you are fine). Don't think because it worked fine on the last tour that things are the same.

cyccommute 

Several things jump out about the Backpacking Light article. First, there is this:

I agree whole heartedly. Bacteria need nutrients and water. Most water is going to be too low in nutrients to allow for survival of the bacteria out in the open water so it is going to anchor itself to something and take nutrients from the matrix or grab nutrients as they float by. The material that the bacteria anchor to...the matrix in the article...is most likely going to be plant based materials or perhaps other biologicals like dead animals.

But bacteria are large organism, relatively speaking. Filtration is enough to get rid of them.

Again, I agree but with more reservations. The growth of a biofilm depends on the nutrients available. The filter element doesn't provide any nutrients so any growth of a biofilm would depend on trapped material from the stream water being filtered. Additionally, the filter element isn't a good matrix for bacteria to set up housekeeping. Cleaning the filter after each use goes a long way towards removing nutrients and to preventing growth of bacteria. Drying it out after use or even occasionally would reduce biofilm growth.

This doesn't matter however except that the filter can become clogged. The bacteria doesn't pass through the filter...it's too big.

Again, I agree but this time they have missed the point. Using chemical oxidants to kill pathogens is a concentration problem. You have to have a high enough concentration of the oxidant to kill the pathogens and not have to the oxidant get involved in side reactions that are using the oxidant on material that is benign. There is also a limit to how much oxidant you can use before it becomes hazardous to consume.

Now the real fun begins Hypochlorous acid forms when chlorine gas reacts with water. If you are using chlorine gas for sterilization of water, you are forming hypochlorous acid. The chlorine gas doesn't disinfect the water, it's the hypochlorous acid formed that does the job. They don't seem to understand this since the authors of the article treat them like they are two separate processes. They aren't.

They are correct that the chlorine gas, as well as the hypochlorous acid formed, and the chlorine dioxide react with the matrix that the biofilm has formed on. Therein is a large part of the concentration problem. All of these oxidants are indiscriminate. They react with anything that can be oxidized in the water mixture. If you have a bunch of twigs in the water you are treating (which also carries that biofilm), the chlorine and the chlorine dioxide will react with a component in the wood that is called lignin. Lignin in sapwood makes up about 18% of the wood but it is much higher in bark...about 25%. If you remove those twigs from the water, your chemicals will be wasted on that material. Even in "clear" water, i.e. water that appears to have nothing in it but hasn't been filtered, there can be microscopic bits floating around with biofilm all over them. That's going to suck up your chemicals. If your chemicals run out before you have killed all active organisms in the water, you risk drinking unclean water.


That's most of the reason why Aquamira is suggested for treatment of "potable" water. It's to polish the water after it has been through some other kind of treatment. I'm sure it does a great job and I have nothing against chemical treatments...as a secondary treatment. Filtering will get rid of most everything but viruses and the virus load even lower than the bacterial load in water. In certain parts of the world, filtering potable water and then treating it with a chemical oxidant would be a wise idea. The US and Europe have very good sanitation systems that keep most of the bad biologicals out of the water.

My job, by the way, often entails using chlorine dioxide to remove lignin from wood. I have to work with concentrations that are dangerous to humans because lignin can suck up a lot of chlorine dioxide. I've actually experienced a couple of the "puffs" I detailed above which are both thrilling and scary.

cyccommute 

Do your really check all your equipment before a tour? Set up your tent, get out the sleeping bag, test the pad, fire up the stove, make sure your fork is working properly, etc.? Testing a water filter before a tour is on the same level as making sure your fork is working. I've had a couple of filters over the years and never had to "test" them before use.

As for proper storage, I used my Sawyer filter once, as in a single time, as in not more than one, as in less then 2...this is staring to sound like the Holy Hand Grenade of Antioch...and after that single use I stored it according to Sawyer's instructions. I back flushed it, let it dry and put it in the bag. What more could I have done? What more would you have done? Testing a water filter before a tour is on the same level as making sure your fork is working

There is a whole lot of Monday morning quarterbacking going on in this thread about the Sawyer. Honestly, drying out the filter doesn't seem that extreme to me nor should I have expected the filter to become nonfunctional after a single use. I'm not the only person to experience this problem and, if I were to buy another Sawyer, I would test the damned thing before each and every trip. But I'm not about to buy another one because I would have to test it before every trip and I'd be worried if it dried out on me.

veganbikes

Yes I do test my equipment or at least pull it out and do an inspection before packing it. My spork is a well used item that I keep in my pocket because I have found it handy in normal life not just for touring and hiking. I don't currently have a tent as I mainly use the hammock (but am planning on getting one and would probably set it up before I leave even if not for testing but for a refresh of set up) but I do inspect the hammock/accessories and if possible I try and set it up. If I had a filter I would probably at the very least inspect it and make sure it would still do it's job.

Basically stuff I use more regularly I don't worry about as much it is the stuff I use less that I make sure to test out or maintain as needed. My touring bike always goes in for a pro-tune a couple weeks before I leave just so everything is good and I can make sure to get some ride time in before hand.
However I was not specifically going after the Sawyer, yes my comment had some grounding in the issues people have had with theirs but was also just a general comment. I believe people should check their equipment, it is not something that is going to hurt anything and it refreshes you on setting up or working the device just so things are smoother on tour.

CliffordK

We do have giardia in some of the streams here in Western USA. I have a little pump filter that I take backpacking. It is lighter than taking a bunch of water.

I can usually carry enough water for a day trip, but would carry the filter for an overnight trip. However, I have been known to just get a cup of water out of what appears to be a fast flowing small, fresh water stream.

Giardia, of course, has a long incubation period, so you won't know until long after one is back home.

cyccommute 

"Inspecting" is different from "testing". There is no way to determine if the Sawyer filter is malfunctioning by "inspecting" it. Even if that I would have known about the calcium buildup issue simply "inspecting" the filter wouldn't have told me if I had the problem or not. Even if I had "tested" the filter (without prior knowledge of the calcium buildup problem), dried it out and put it back in the bag, I could have caused the same problem because it happens when the filter dries out. I did "inspect" the filter to determine that all the parts I needed would be there. This is a not an issue that occurs all the time but it is known to Sawyer and a heads up in the instructions would have been in order.

I don't "test" stuff following storage because I don't put away broken equipment. If something is broken, worn or needs replacement at the end of a tour, I fix it, mend it or replace it. I'm make sure that I'm familiar with the operation of a new piece of equipment before I go using it on a tour but this filter was not something new. I had used it before hand and it worked well. Since the filter was in good order before it went into storage and since I had no reason to expect that the filter wouldn't come out of storage in the same order it went into storage, there was no reason for me to not expect it to work in the same manner as it went into storage.

A further issue which will keep me from trusting hollow filters like the Sawyer again is that I live in a state where water evaporates quickly. I have no idea how long it would take for the calcium clogging issue to happen nor the parameters needed to make it happen but I'm not prone to leaving my water filtering equipment wet for extended periods. The whole biofilm discussion above has some merit. The best way to avoid build up of that biofilm is to not give it the conditions for it to happen. That means drying out water filtering equipment. If a Sawyer filter can clog on drying and need an acidic flush to re-establish a fraction of the flow (it doesn't all come back), I wouldn't want to depend on it for something a critical as water.

Again, this is not something that anyone would reasonably expect. The filter came to me dry. I used the filter a single time and filtered clear water from a clear stream at 11,000 feet where there is zero mineral load. I was less than a mile from the headwaters of the stream and the stream flows over Colorado granite which is composed of feldspar and quartz...to minerals that have a very low solubility in water. I dried the filter prior to storage and had no reason to expect that it would be clogged with anything. I've used hollow filters before at work and they will go for years and years before even slowing down. There is simply no reason to expect the filter would fail after a single use.

To use a bicycle analogy, this is akin to putting brand new cables on a bike and not using it for a couple of months only to find that the cables had dissolved. It's not an expected, or even conceivable, problem.

veganbikes

I understand testing is different from inspecting but in my case certain things don't quite need a test (like sleeping bag or something along those lines)

I also disagree with not testing equipment when you put it into storage. Things can happen from something just sitting around. One should never put anything away broken and one should fix or mend broken stuff but you should double check it before you go.

For a bike analogy, it is like putting up a bike for a while and the tires crack and fall apart. They were fine when you put the bike in storage but due to various conditions your tires are in poor shape and the bike probably could use a tune up and maybe some brake pads.

A filter is subject to the same temp., humidity. light... changes that everything else is subjected to. It is unfortunate that those things happened to you but they can happen. That is really what I am trying to say. Unexpected things can happen and you want to make sure your gear is ready to go when you are. I understand it is a pain and maybe impractical to test something like that but it won't hurt you and could make the trip better.

I do understand your point about the cables but in that time those cables could rust or something might have gotten on them that corroded them away.(I work in a shop and I have seen that before) It isn't likely to happen but as I said above unexpected things can occur.

staehpj1

Just a couple other things to consider before choosing what filter to carry...

The squeeze and mini each cost less than a replacement cartridge for most of the pump type filters, so if you need a new cartridge it is actually cheaper to switch filter types. My experience is the they last longer than the pump cartridges as well.

The squeeze and mini are light enough that if really paranoid about filter failure you could carry two and still be substantially lighter than most of the pump filters.

There are lots of factors to consider, but after using an MSR Sweetwater for years I have been really happy using the Sawyer Squeeze and Mini for the last few years. I find that for most tours a filter isn't really worth carrying, but when they are 2 or 3 ounces carrying one makes sense more of the time.

cyccommute 

Water filters should fall into the same category as sleeping bags. There is a very reasonable expectation that a functioning water filter placed in storage should still be a functioning water filter when taken out of storage. If the manufacturer was aware of a potential problem...which they seem to be given that they address this problem in their FAQs...they should warn the customer in the instructions so that proper precautions can be taken.

I think I said you should fix and mend equipment before placing it in storage. But, honestly, there is little that can happen to most equipment that is properly stored. "Properly" is the key. Sleeping bag manufacturers warn you not to store bags in compression sacks. Tent manufacturers warn you not to store tent damp. Stove manufacturers caution you about storing stoves with fuel in the lines. Other water filter manufacturers tell you to dry the filter before storage. These are all reasonable precautions to take and, more importantly, have been suggested by the manufacturers.

Now if something external happens in storage, like your house gets flooded or your children decide to play with the camping equipment or your dog chews the end of a stuff sack off, then, yes, I would say that the equipment would warrant inspection and even testing but just sitting in storage provided that it goes into storage in good condition isn't enough to warrant a complete test of all your equipment

The Sawyer filter has problems with being dried out. You can find all kinds of reports on-line from people who have had the very same problem I experienced. They all were as unpleasantly surprised as I was and none of them seemed to anticipate the problem. And, again, why would they? There is no reason to suspect that the filter wouldn't work. And, as I said above, since this is a common problem, what is to keep it from occurring while you are out in the field?

You aren't understanding the problem nor the analogy. Tires reacting with ozone is an expected phenomenon. It's akin to storing a tent wet or leaving a sleeping bag in a compression sack. It's also something you can visually check. This filter not working after a single use following storage is highly unexpected and somewhat bizarre...hence my comparison to your cables melting for no apparent reason.

But it isn't light, temperature nor even changes in humidity that have caused the product to fail. What you (and many others) have been saying is that every single piece of equipment should be tested thoroughly before you put it on the bike. I'm saying that that ismostly unnecessary, largely counter-productive and unrealistic. I have never had a piece of equipment that I have used previously fail as spectacularly as this filter did. I've had new items fail but I don't take something right out of the box and hit the road. Testing something new...tent, sleeping bag, pad, stove, etc...is realistic. But testing every piece of equipment that you have used previously isn't.

I would hazard a guess that you haven't seen a cable decompose for no particular reason after a single use when stored properly and not exposed to anything that would cause it to corrode. Don't get hung up on the cables but focus on the "unexpected" aspect of the analogy. Yes, the unexpected can happen and there are ways to deal with that when it happens. But, to use a bit of Donald Rumsfeld language butchery, there expected unexpected events and unexpected unexpected events. The problem with the Sawyer falls into the later category.

I agree that you don't really need a filter on most tours. But I have to disagree about the Sawyer. Personally, I'm not going to be paranoid about filter failure because I'm going carry a filter that I know works when it comes out of storage. It doesn't matter how light or how inexpensive the Sawyers are if they fail so easily. Carrying two doesn't really solve the problem and falls into the "belts and suspenders" realm of touring. I've been badly burned once, I don't need to be burned again to learn my lesson. Yes, something like the Sweetwater is a bit more expensive and a bit heavier but if it works, it's worth the cost and the weight.

And, if anyone asks for my suggestions, I'll tell them to stay away from the Sawyer. I may tell them to steer clear of any hollow fiber filter system.

robow

At least this thread's debate has been good for one thing, it made me rethink as to whether I had taken apart and dried out my Katadyn pump/filter when used last summer.

DOH!, it was still wet within and growing thingies?.......time to replace the pricey filter.

cyccommute 

Probably not. A weak solution of chlorine bleach followed by copious washings with water should do the trick.

By the way, since it was Christmas Eve and nobody wanted to get too involved in anything related to work science, my colleagues and I spent the day yesterday speculating about this problem (many of us are very outdoorsy because we live in Colorado...it's just another room with a spectacular view) and we've come up with a hypothesis of what is happening. We don't think it's related to any kind of calcium build up, considering that my filter never came with in 50 miles of a calcium source. This is some educated guessing and some wild speculation but here goes.

We suspect that the fibers in the filter are a cellulose ester that, once wetted and then dried, stick together and clog the hollow fiber. The reduced flow isn't because of calcium salt build up but because the tube is restricted. The fibers don't swell upon wetting with water, hence the continued lack of flow even when wet again. Flowing acid through the filter doesn't remove the calcium but swells the fiber and breaks down whatever chemistry that is going on to close the fiber.

Cellulose ester is a plastic made from cellulose. The most common example, and the highest usage, is filter tow for cigarettes but it is also used in making film stock...you know the stuff we grandpas used before the damned digital camera I don't have a lot of experience with the actual cellulose ester but I do have lots of experience with making the cellulose that goes into making the ester and it can have some weird properties related to water content and where the paper was made. These properties may translate over to the cellulose ester and may even cause more problems for me here than for others in more humid climates.

Cellulose goes through a hysteresis of strength and other properties based on it's water content at the time of production. I'll use strength as an example but other properties follow this same trend. A paper made, and dried, in a high humidity environment like the southeast US or northwest US has a certain strength. If you take the paper to a dry environment like Colorado, the strength property goes down as the paper loses it's moisture. If you take it back to the humid environment, it gains back strength but not as much as it originally had...that's a hysteresis.

Now if you make the paper here in Colorado and let it dry, it has a similar strength but the moisture content is lower. Take that paper to a humid environment and it goes through a similar hysteresis but the strength lost is less and redrying the paper results in a lower strength loss in the end. We should make paper here in Colorado but we don't have the trees nor the water for the process and the end product is too cheap to make enough money by shipping the trees here.

I believe that the problems I had with my filter are related to a similar hysteresis that is related to the difference in regional humidity. Our absolute humidity in Colorado is much lower than the absolute humidity elsewhere in the US. Our thinner air means the air can't carry as much water. Our relative humidity is also lower because we don't get as much rain on the lee side of the Rockies. Both of these conspire to dry out my filter more than places like Maryland or the Midwest. When I air dry cellulose, I end up with a moisture content of from 4% to 7% depending on the time of year (winter is drier). People in the eastern and northwest US have moisture contents double to triple the highest moisture levels I measure...closer to 12 to nearly 20%. When they "dry" their cellulose or their water filter, they have a higher water content which keeps the tubes from collapsing. When I "dry" my filter it really does dry out and the tubes pinch closed.

It makes sense that staehpj1 could use his filter forever without every experiencing a problem and that I would experience a complete failure after one use. I think the only way that I could keep my filter operational is to never let it dry out. That opens the door to biological issues which I'd rather not deal with.

staehpj1

Interesting hypothesis. It sounds reasonable, anyone want to try to verify it?

That seems way more likely than calcium build up.

Assuming you are correct...
Starting with a working filter and keeping it in a sealed bag or capping the ends would prevent complete drying. On the other hand after use it probably takes quite a long time to fully dry so unless you will be in a very dry environment for quite a long time between uses I'd guess it is unlikely to be a problem.

robow

Thanks for the suggestion, but since this filter was likely 10 years old, I think Santa took pity on my stupidity.

cyccommute 

Storage is always going to be an issue, however. You probably don't want to store it wet to avoid mold. The other problem for me and others who live out West, is that it doesn't take long for anything to dry. There's a lot of space out here in the dry West

And, like I've said numerous times above, unless you know about the problem, you are in for an unpleasant surprise.

Tourist in MSN

If my fork stopped working, I would use my spoon. No I do not test my fork before taking it on a trip.

staehpj1

I still am pretty happy with my Sawyer filters and will continue to use them. My MSR Sweetwater needs a new cartridge and I doubt I will ever buy one for it.

I have used the Sawyers mostly in the dry west. I don't think mine ever got all that dry when on a tour or backpacking trip though, since it is usually in a plastic bag to keep the water segregated from the rest of my gear.

I was curious just how common the problem cyccommute reported was so I read all of the reviews of the squeeze and the mini on the REI site. There were a lot of reviews (somewhere between 150 and 200, I think) including a fair number of negative ones. The negative ones were mostly folks complaining about bursting the bags. A few were about trouble filling the bags, and a few were about the rubber washer leaking. I didn't see any about the problem he described so I have my doubts that it is all that common. The things folks were complaining about were all things I find I can deal with.

prathmann

I have one of the UV water purification devices that I've used on backpacking trips. But I've never taken it along on a bike tour since my tours have always been on roads in areas where potable water is pretty easy to obtain.