Backcountry Water Treatment, Part 3: Microfiltration 

Your work is an incredibly massive breath of fresh air compared to so many of the RU-vid gear review/technique channels that come off overly click baity. Not to mention, I actually learn so much from every video you do! They are packed with incredibly desne, great content, I could watch them multiple times and still learn new things each time... or I could gain a better understanding at something I only grasped the edges of the first go around. Thank you sir!

The pure amount of time invested into this video is wild. Thank you sir, for the AMAZING videos you create. This is literally one of the best, most educational, raw information dump on RU-vid. DUDE, HOW DO I GIVE YOU MY MONEY. I would really love to support you if you have T shirts, Stickers, damn, I’d cash app or Venmo you, out of sheer appreciation of your content. From the bottom of my heart. THANK YOU.

The advantage of getting giardia is that, not only did you not need to carry extra water filtration equipment , but you also become lighter through the process.

One more thought on sawyer longevity (and probably other hollow fiber filters). With hard water, you have to do a vinegar soak once in a while to maintain flow rate. I think a lot of people don’t know that. I didn’t know when I first started using my Sawyer micro, and I was really disappointed with the flow degradation… then I saw the instruction to do a vinegar soak between trips, and I’ve been much more satisfied since then. Great video! So much good info!

You are absolutely talking about the things that actually matter and exactly no one else is discussing them.

The time and effort you've put into this is phenomenal, thank you ♥️ What an amazing video

My autistic brain that is prone to hyperfixation and going down the rabbit hole for my special interests loves your videos.Thanks for sharing this valuable content with your audience. You must be protected at all costs.

One thing I'm not understanding well is how these filters have much lower log numbers for cysts, which are bigger, than bacteria, which are tiny. How are cysts getting through holes that stop almost all bacteria? Thank you for the incredible series of videos!

A couple years ago, I took my son and nephew on a 3 day backpacking trip. We only used a sawyer filter and gathered water from a fast flowing river. We used one filter with a large bladder to fill our water bottles. My nephew got giardia and had symptoms for over a month. My son and I were fine. Thanks for your work, chlorine dioxide now added to the treatment regime

Man do I appreciate this video I actually felt like I got a solid answers not just more information, I’m greatfull

Anecdotally being one thru hiker with more than 6000 miles I have never gotten LaGuardia 😂 on my AT NoBo thru hike I started calling it LaGuardia. I even let some folks think I thought that was the actual name and it entertained me to no end. I used polarpure never ending iodine treatment that trip. On the PCT I used aqua Mira drops. Hikers around me did get sick and I noticed most of them didn’t take care of basic their hygiene. Dirty ol dirt bag hikers. Anyway I thought you might enjoy my personal experience with this. I’m also a wilderness guide, WFR, and a Master naturalist. Love the video! 👍👍

This informative series is important not only for hikers but for those of us that live in the far back country and have to figure out how to filter and clean the water for our homes. You are a HERO!

You absolutely succeed in your goal to have the viewer think again about his past choices. Even though these are "tough" videos based on the amount of information/data you go through I cannot thank you enough in bringing this info in a very very digestible form. I always go on the lookout for more of your videos even though my brain needs quite some time to put everything into place :). Thank you

Another amazingly high quality video. At this stage I would expect nothing less - you always have such detailed and well researched information! Thank you for putting it all together. I live in Europe and have an Alpkit Hippo filter. It removes 99.9999% waterborne bacteria (E.Coli, Salmonella, Cholera) and 99.99% of protozoa (Giardia, Cryptosporidium). Not as high as the Sawyer but I'm glad it's above EPA standards. It has a lifecycle of up to 3000L apparently.

Have you though of making these available as podcasts? 95% great to listen to on trail, even without the visuals!

Dr. Skeptical you are a treasure! With regard to a subsequent video a lot of people are not aware that the early Spanish explorers were not searching for gold but, in fact, were searching for the " Skep's trail mix recipe". Sadly , like the seven cities of gold the recipe was never found. How revolting!

Fantastic video! This has really changed my perspective on what to look for in a water filter. I'll admit I was very much guilty of assuming that all filters worked "well enough" so the removal numbers didn't matter and just looking at flow rates, cost and ease of use was enough. Funny how epidemiology can be a stark illustration of the importance of a good understanding of statistics! Definitely rethinking my water treatment strategies for backpacking after watching this, so thank you for taking the time to research and present it all!

I live in north eastern Nebraska…agriculture and animal husbandry w/cow feed lots abound. I use a water filter as a pre filter then use a water purifier as a final. That way the filter saves my purifier filter and I get higher water volume out of it. Also, I disinfect both filters’ intakes and wash my hands. I back flush as well. Each filter (pump and gravity) is stored in its own carry bag. I’m retired military and a lifelong outdoors gal and saw early on how failure to follow personal hygiene in the field can lead to misery. It only takes a few minutes to filter, wash and store the water filtration systems needed for an outing. Proper waste disposal is required as well. Complacency and laziness are all too common out there.

My favorite pedantic youtube nerd ever is back with a new video! Keep up the good work brother. These are exactly the kind of videos RU-vid needs in such a sea of misinformation and click bait. Also a suggestion- Any interest in making a video or series about sleeping bags and warmth ratings? I know there's a lot of confusion out there about advertised temperature ratings versus real ratings. I figured you would be just the kind of guy to give a well thought out, researched and detailed approach to the subject. Cheers, Lou

Love this series!

Excellent series. Valuable. Thanks!

This is backpacker's college. Love the way you break everything down. Reminds me of my analytical classes I've taken.

Fantastic Series you are putting together. I really enjoy the academic and analytical perspective you bring to the topic!

Always a treat to watch one of your videos

This is seriously a great piece of work. Thanks so much! PS: Im glad my sawyer stands out well in your testing :)

In addition to possibly the most useful backpacking content I’ve seen on YT, as well as your spirit of generosity in sharing all of your work,I must say I really enjoyed your sense of humor! Many a time did I laugh out loud, catching the little winks (i.e. lake Titicaca) and more obvious jokes (i.e. Must be great cause it shows a picture of backpackers) sprinkled throughout the series. Made it fun and amusing to learn! Bravo

I was excited when I looked at my phone during the Superb Owl game and saw that you had published a video again! This is the kind of quality content I wish I could find on many other kinds of topics, and I'm glad you exist for hiking gear!

I love these videos! My already existing skepticism has been magnified greatly after watching your videos. I'm looking forward to sharing my newly found knowledge with fellow PCT hikers this season.

Great to see another video from you my friend! Your content is always absolutely excellent, thank you so much for your work and your contributions to this field :))

Another excellent presentation. I’m really enjoying them. Thank you.

commenting for the algorithm, but youre the goat in this niche right now and im loving these vids

Outstanding level of detail and commitment to real world evaluation. Thank you!

Thank you so much for putting out these videos for us, your work goes above and beyond, so detailed and informative. I’ve got pages and pages of notes from watching your nutrition for hikers series and it’s been really helpful for me, it was like taking a short course! Always look forward to your videos and never thought I’d be excited to see a part 3 to a water treatment video series but here I am! I look forward to part 4 :)

WOW ! I am again in awe of your multiple series of my 'bible' chapters ... ultralight calories, water filtration ...

All I can do is express gratitude and appreciation for your content. Fantastic. Thanks again.

I just found your channel today and I'm hooked. This is the kind of research that's very valuable and entertaining at the same time.

Wow, that's such surprising information about the water from the campground faucet being the highest concentration. That's where i normally fill up. Interesting info!!!

Holy grail of clean water information!!!! Your work is amazing!

Wow, really enjoying the series. It’s a master class on water purification.

I found your channel about 2 weeks ago from the prepaid airmen and I love the content, immediately subscribed. Thank you.

Okay, I'm a believer now. Well done, as usual!!

Sweeeeeet! The best water videos I've ever seen!

This is literally the best backpacking channel I have ever found. Thank you for all the effort and time you put in!

Truely masterful research, analysis and interpretation. A sincere thank you for the time that goes make to produce these videos. A lot of information to take on board, but I'm very much enjoying the process.

I've been waiting for this video in particular as I prefer to filter. And after watching, am (mostly) content with my Sawyer Squeeze and Katadyn BeFree filters, though might go with the combined approach in certain circumstances. Thanks for all the time and work you put into your videos! It allows me to save my own many nerdy calculations and much research time for my gardening projects or the occasional acquisition of new gear.

Thank you for that educational video!

Man you should have 1 million subscribers. Thank you for putting so much work into all your videos

I wish everyone in this vertical of youtube had the quality and information you put into your videos. Delivery of the information is top notch as well. I could listen to you all day.

Watching this video made me realize I'm not the only one going down these rabbit holes with gear (which is good news as I thought I was crazy). Great video in an even greater series! Thanks for putting out such good content

Thankful for the risk reduction afforded by the sawyer filters over the last decade of outdoor adventure! I switched from the mini to the squeeze about 9 years ago for the flow rate benefit like you mention. Glad to see sawyer ranking at the top of these comparisons and that they most openly share lab testing. Great video series!

I started backpacking in the 70s and for about 20 years I never filtered my water. I never got Ill. Then I purchased an MSR pump filter. It was heavy but did the job. As I aged lighter gear has become more important so for about 10 years I used chemicals and I also had no issues. I now use a Sawyer and it’s been good. No issues. For now I am happy. If I was doing something like the PCT I would bring my Sawyer and chemicals. I would filter then treat it. I must add most of my trips take place in the White Mountains of NH and the water sources seem pretty clean. Probably better than the crap from my home tap. Good video, thanks

Another superb video. I use a pair of Sawyers daisy chained one directly above the other, exactly for the function you mention at the end!

Big thanks for putting this together...this is a huge help (Pass the Decimal on da left hand side!!)

Thanks for this extremely useful video. I was made aware of you by one of my viewers, as I'm addressing water filters right now. I learned a lot. Thanks again and will be watching the other videos as well of course !

Another amazing video on a very important topic. Thank you. I really hope you include a section on UV purifiers in one of your future films.

Everything in this channel is highly brilliant. Hands only produces a recognizable tone. Info is well researched. Humour is intelligent.

Very informative I’ve been looking for a good source of info like this for a long time.thanks very much appreciate your time and effort.😊☮️

Thanks so much. Very comprehensive, useful info as always.

Loved your hands in this one.

Excellent video!

What a great video! As a former user of the Sawyer Mini the flow rate was unbearable and I would often find myself not using the filter because it was so annoying. Bought the Platypus Quickdraw filter and the difference is like night and day, I almost enjoy using the filter now! Even if the filtration is not as effective atleast I am now filtering the water I drink every time. Don't know about the longevity of the filter yet though, havent used it too much yet.

Great video like always.

Fantastic contents. ❤

Every one of the GearSkeptic videos is a masterpiece.

This is freaking fabulous!!

Part 3! Niiiiiice

I carry a BeFree and a Sawyer mini. The BeFree is terrible with dirty water, I prefer to use it on canoe trips when I can scoop "clean" water from the middle of a lake. Once at camp the Sawyer gets setup on a ridge line with a larger feed bag.

Very interesting series you have going here. I'm very interested to see your take on Steripen. Efficacy of the Steripen looks good on the surface, but you really dig into the details and I'd love to learn what you uncover. One thing that I frequently see mentioned, but never quantified, is that UV sterilizes rather than kills and that some pathogens can reactivate after a period of time. I've never been able to find any indication on how long that might be and to what degree. I'm also wondering if you've done any looking at small micron monofilament nylon mesh filter bags. 25 micron bags are relatively easy to source and have great flow rates. Smaller micron bags are available, but a bit tougher to source and based on my experience with both 75 micron and 25 micron bags, I would expect affect on the flow rate to be noticeable at much below 25 micron. It just so happens that 25 microns is small enough to filter out some of the larger unfriendly bugs (some protozoan cysts, for example) and does a great job of removing particulate that might otherwise hide the bugs from the UV light. We've been using a 25 micron bag for the last few years as a particulate pre-filter for a Steripen while hoping that we were also gaining some level of purification help as well. Either way, they do a great job of removing the wonderful floaties in the water and they are super light at around 4g for the one we use. Regarding your comment at the end about using a filter more than once on the same batch of water to increase effectiveness, I have to wonder why some of the harmful critters made it through the first pass. I'm actually quite curious why the filter process isn't more pass/fail. Is it because any bugs larger than the filter pores fail to make it through, but ones that are the runts of the litter fly right through with no problem? If that is the case, I would expect the second pass through the filter to accomplish very little. Is it instead because the filter has a small number of "defects" where the pore size is either larger than expected or a failure in the medium causes that same effect? In that case, multiple passes through the filter might result the same percentage of pathogens taking the freeway each time, but with the overall population reduced on each pass. That might also explain why the filter fails to filter the larger pathogens at 100%. The Sawyer datasheet you included suggests the former as they seem to claim the latter is not possible. They go as far as to say "No harmful bacteria, protozoa, or cysts can pass through the SawyerPointOne Filter" and that "No pore is larger than 0.1 in the Sawyer PointOneFilter." If the largest pore size is 0.1 micron (μm), how on earth do we have these little guys making it through? From en.wikipedia.org/wiki/Bacillus_subtilis, "B. subtilis cells are typically rod-shaped, and are about 4-10 micrometers (μm) long and 0.25-1.0 μm in diameter". www.ncbi.nlm.nih.gov/pmc/articles/PMC8123537/ indicates the size of R. terrigena to be 1-2 micron. www.tandfonline.com/doi/pdf/10.1080/23311932.2019.1569830 says it's "cell shape was short rod, with cell length of ... 1.60 ± 0.08 μm." Unfortunately, they don't give a diameter, but a photo of a slide from the first article suggests the rods to be maybe 2-3 times as long as they are wide. That would put the low end of diameter at about 0.51 micron. M. luteus also seems to have a size of around 0.5 micron. That's at least a full 5 times larger for the last two than what the Sawyer should "Absolute"ly filter out. Something has to give since a few of the bugs are still making it through. I wonder what it is?

Wow! Thanks.

Yeah... I'm waiting for this 😘🥳🎉 thank you 😘😘😘😘 greetings from Taiwan 🙋🏼‍♂️🌴

You dropped this, 👑

this is another great instalment in your water treatment series. i wonder if it would be possible to mention the best ways of eliminating as much as possible crop chemicals or heavy metals in water supplies that may fall foul of agricultural run-off. thank you again for analysis

Amazing series! We need more people like you. Maybe some of the science channels would be interested in a partnership or something like that.

thank you! did i miss where you gave data on the sawyer squeeze? you refer to it constantly, but every time you get into specifics, you only use the mini (but i could have missed!). where does the squeeze sit in your comparison/analysis?

Extra job!

Might I suggest a vid on silt removal via coagulation?… … it’s an advanced for topic for backpacking, common for rafting rivers, and used ~every minute in ~every water treatment plant worldwide. I suggest comparing the classic flocculant alum to modern polymers.

I'll be honest I didn't watch the whole thing, so I may have missed it, but one important factor to consider is being able to check the integrity of your filter and whether it is still filtering correctly. One of the reasons why I selected the Katadyn BeFree over the Sawyer was because you can blow into it as a test to see if the filter is still good or not. Not sure how good of a test this is, but this is what Katadyn says to do and it does give me more confidence when using it to know that it is still filtering correctly.

Don't know if you have plans for a part 4 but how about covering flocculating agents? Love your work!

Are you an engineer or biologist because I love this methodology and it ain't on RU-vid enough!!

Oh man, this is gonna be good

Great content

Thank you very much for your nice review, I love it... But, us I am another "skeptical", in this peer review context that RU-vid provides, here it is what I missed: when speaking about filtration "size matters". Reduction provided by hollow fiber filters depends both on the average size of the tiny pores that this hollow fibers have and in the size of the particles that you are intending to eliminate from the water. In this case in the size of the bacteria, protozoa and viruses. Obviously viruses are too small to be retained by the filters, so they are out of the equation. Eukaryotic protozoa cells are much bigger than bacteria cells. So, if a filter claims a reduction of six logs for bacteria, expected reduction for protozoa should be much bigger. IMO, filtering is a safe option for protozoa risk and for bacteria in most circumstances. For worse scenario, combination of filtering first and chemical treatment second would provide a enough safety level. I'm not sure if filtering twice would provide the same safety level: bacteria small enough to pass the pores the first filtration would be able to pas it again in a second filtration. I know that there are other factors influencing this, like distribution of pore size, so more investigation on this would be needed.

Love your videos. Thank you for your time and energy! Was also curious about the you make chlorine filters by using salt and electricity. Snd of course uvb filters. Also wondering if leaving your filtered water sitting in direct sunlight how well microorganisms are reduced.

Excellent information. Somewhere in the gear room, I have a bottle of flocculant concentrate meant for really muddy water, but I don't know much about using it. Might make for good content. My experience with all three Saywers and the Befree is that you will essentially need to replace the filter every 1.5-2ish years if you're a weekend warrior hiker doing 10-20 trips a year. YMMV but I notice no difference between them in service life before they get so agonizingly slow, you can't use or clean them any longer. For pre-filters, I've seen two pretty interesting if fiddly bits. Millbank bags seem to be a British army thing and let you pre-filter solids from the water. I've spoken to someone who swore by using filters meant for making biodiesel. Not a clue if they are safe for drinking water, but they appear to come in fairly fine mesh sizes. I always wondered if I could combine the two products. I purchased something that looks a bit like a condom that goes over the stem of my Befree on Amazon, it didn't end up working with my hydrapak soft bottles so I've never been able to use it.

After seeing that hilariously high contamination straight from a faucet; I feel much better about always, regardless of source, filtering through my sawyer.

Thanks a ton for this video and I'll definitely think about getting a purifier, don't know how safe water is in Sweden though.

I was looking at using a Sawyer SP160 and after looking at some rather disgusting throughput I found the Katadyn Steripen (sediment) Pre-Filter which will fit on the Sawyers input opening. This, I hope, increases use, longevity, clarity and reduce backflush requirement.

This man is amazin

You are the goat

Thanks for the video, I will drink many quarts of safer water with this information.

What were the odds that I would discover such a research heavy channel with such interesting topics right as I start getting into backpacking. I'd say around 5 log

Great content. I wish you touched on leptospira as these buggers seem to be uniquely small. I've read a lot of conflicting data whether they will be filtered out or not. I suppose my best option is to filter and chemically treat the water.

Fantastic video! Thanks so much! Question: I hike a lot in Europe and most of the hikes I go on have 3 types of water sources. 1) water springs where pipes come out directly out of the ground; 2) cattle/sheep/goat water trough 3) rivers and streams (some fast most moving some slow, some in high elevations some in low, some with in areas with some animal husbandry (cattle, sheep and goats) and other without; I would love to know the concentration of pathogens in these types of environments (particularly 1 and 2). If springs are really clean (as I've been told) presumably I could get by with much less Log protection. Similarly, in the water trough I've seen, I assume the animals do not crap in it (I could be wrong) but put their mouth in it. That being the case, I wonder how much are the pathogen concentrations in this water source type (and what filtration protection I could get by at. BTW, in the last cast I had always used the chloride dioxide tables too (but sort of by chance since I was too grossed out by the water). Your last video on chemical filtration vindicated my hunch (thanks again). Also, these series highlighted the invisible risk of swimming in watering holes that I've seen many hikers jump into (and I've often wanted to as well but mostly don't actually do - particularly still waters).

Odd question referring to your rough math at 37:00 to 37:30. If a CFU consisting of 10 cells were to enter a filter, wouldn't that make it easier for the filter to catch it just on size alone? I guess this entirely depends on how well the cells stick together, or if they easily separate once they reach the filter. This is something that I know literally nothing about(as you can probably tell). Also just want to add this isn't antagonistic, just genuinely curious. Your channel and every one of your videos are amazing and have made my backpacking experiences significantly more enjoyable. truly can't thank you enough.

As usual, great video series! Ignorant question here: Do these filters aid at filtering major particles like say for example a mountain river with lots of sediments in suspension? Is the efficiency reduced?

once again an excellent video, please take the steripen for your next episode ( virus). there is no profound information about this either, except for the advertising statements.

Hi! Just trying to remember which Sawyer filter you preferred over the others? Was it the mini? Thanks! Deeply love all of your videos

Big Steripen fan here. I would love to see a comparison of Steripen to Sawyer. I'm just afraid my sawyer squeeze will clog and I won't have any clean water to backflush with. Of course my Steripen could also malfunction. After watching your videos, I'm getting some ClO2 tabs to replace the iodine tabs for a backup.

Love your work, and appreciate the time and effort you take. There is one thing you mention multiple times, that in actuality isn't really correct. You mention beaver water or cow ponds as if a Thru- hike is going to mean you're constantly having that issue. New Mexico on the CDT there were plenty of cow troughs and I think I had to get water out of really bad cow ponds twice. There were many places that had rain water containers and water caches. So on the entire CDT hike I think I only had maybe 3 really bad water sources. Were there less bad, but as you say still high contaminated water sources? Sure, but on a thru-hike (excluding the first 700 miles of the PCT and 700 of the CDT) you are likely to pass multiple water sources, and usually we choose the ones that look the best. Or we read on Guthooks about bad ones so plan to skip them. Basically, I think there are some other factors to consider. I used the Platypus Quickdraw on the CDT and thru-hiking across Ireland, Scotland, and Spain). I never got sick from water. And the reason I switched is the slow flow of the Sawyer which I used on the PCT and AT. The flow rate goes down quickly. More so than they advertise and as you said back flushing with as much PSI as they tested just isn't possible on trail. Again, want to say, love your work. The calorie/weight and the videos on recovery were fantastic!

.. What about the comparison of pump filters ,,,, larger filter surface plus increased pressure through filter and then include a charcoal filter before clean container ?? .. Such as the Katadyn Hiker ..