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Dump the Pump Water Filter

My Hydration System
My Hydration System

The first time I tried filtering water from a stream, I knew that the distance I could hike in one day would never again be constrained by the amount of water I could carry. I remember the scene vividly: getting water out of a stream, surrounded by a sea of hobblebush, on West Hunter Mountain in the Catskills. Hiking was never the same for me afterwards. I’d been freed from the limits of my hydration reservoir.

I carried that pump purifier, a First Need weighing 17 ounces, for the next few years along the Long Trail, up the 100 Mile Wilderness, through the Catskills and the White Mountains, and down the Appalachian Trail, until I tried an inline filter and realized I could cut almost a pound of gear weight from my pack. That was the end of the pump, although I still keep it around for just in case we have a water main break (again).

I was asked to write this post for a regular reader who wants to switch from a pump-based water filter to a Sawyer Squeeze or Aqua Mira purification drops and wants me to explain how I use the two on day hiking and backpacking trips. 

My Hydration System

I started carrying two different water purification/filtering methods about 6 years ago so I always have a backup method handy in case one fails. I had an incident on a long trip when my pump-based First Need stopped working completely due to an invisible puncture in the intake hose. I figured out the problem eventually, but it was a wake-up call for me to carry something extra like chlorine dioxide as a backup purification method.

I’ve been using the current lightweight system for a few years now and it works really well for me:

  • 2 x liter plastic Aquafina bottles, my favorite brand of bottle. These are only used for “clean water” and are never dipped into streams or springs to be refilled.
  • 3 liter Platypus reservoir which can hold 3.5 liters. Platypus doesn’t make this size anymore, but a 70 ounce Platypus also works well. The Platypus is the only container which is used to collect or hold “dirty water” which has not been filtered or treated with chlorine dioxide. The reservoir also boosts the amount of water I can carry for dry stretches of trail or if I want to dry camp away from water sources.
  • Sawyer Squeeze Mini (water purifier) – weighs 1.38 ounces
  • Aqua Mira water purification drops – the active ingredient is chlorine dioxide, but it works faster than tablets because it’s in a liquid solution. The two bottles weigh 3 ounces full but can be repackaged into smaller bottles depending on the quantity of solution needed.
  • MYOG water scoop for scooping water out of small streams made from an old Platypus reservoir

Here’s how I use it:

Cooking Dinner
Cooking Dinner while tending to my hydration chores

When I pitch camp at night:

  1. I fill the Platypus with water and screw the Sawyer Squeeze Mini onto it. (You can get a really tight seal if you wrap the threads of the Platy with white plumbers tape and it prevents the cap from leaking too. ) Water flows through the Mini very easily and squeezing isn’t necessary. Hold up the full Platy and just filter the water gravity style.
  2. I filter 2 liters into the Aquafina bottles: one for cooking dinner and one to drink at night.
  3. I refill the Platypus with 3 liters of water.
  4. I mix and add Aqua Mira drops to the Platypus reservoir and let it sit overnight. This requires mixing 21 drops from each bottle, mixing then together, waiting 5 minutes, and then pouring the mixture into the reservoir. I’ll use this water in the morning for cooking, pre-hydrating, and to top of my drinking bottles. By morning, the inside of the Platypus and the water it contains is considered “clean water.”

I don’t feel the need to pre-filter the water with the Mini before adding Aqua Mira to it. I only take water out of moving streams and it’s always crystal clear. If it were muddy, it would clog the Mini, which I want to prevent. I don’t carry the backflush syringe and have never experienced a complete blockage. 

In the morning:

  1. I use any remaining water in my water bottles for cooking, topping them off as needed with “clean water” from the Platypus.
  2. I drink 1 liter from a bottle to pre-hydrate before I break camp and start hiking.
  3. I top of my bottle(s) and dump any remaining water from the Platypus.

I like to get up and go in the morning and taking care of my water purification overnight, ensures a fast start the next day.

During the day:

  1. I fill the Platypus and filter my water with the Mini, gravity style, whenever I need to refill a bottle. It’s much faster than using chemicals.

That’s all there is to it. While I could just use the Sawyer Mini for all my filtering, I like have Aqua Mira along as a backup. It’s also quite convenient for purifying large batches of water at night, so I can eat dinner and go to sleep earlier.


  1. I’ve been using a similar setup for the last four or five years, but based on Gravityworks system without the clean water bag it comes (use a standard platypus like you have), and I use my cooking pot as a collection vessel if needed (very rare). I like the zipper top bladder for collection only. I used to use iodine as a backup or double protection when filtering from lowland streams or rivers or silted out sources (silt clogs filters really fast), but switched to Aqua Mira a few years back. I gave up the pumps in the early 90’s and will never go back.

  2. Like any water supply, there is no one solution for all conditions that you may encounter. Many years ago when I thought boiling was the answer, it was pointed out that you could concentrate certain minerals & toxins by boiling…making it worse.

    Briefly, there are 5 basic methods to clean water, not counting combinations.
    1) Boiling
    2) Filtering
    3) Chemicals
    4) Radiation (UV-C bands)
    5) Do nothing

    The last requires some forethought and research into the water supplies found on the trail, perhaps a certain immunity to Gardia. I know a gentleman that never treats his water on the NPT in the ADK’s. Not really recommended without extensive research.

    1-4 are all effective. A slightly different methode follows. I use a 2.5L platty as a dirty water resevoir at night. I never treat this. I only use the UV treatment on the two half liter water bottles I carry. I boil water at supper, allowing food to rehydrate under my hat (a pretty good cozy.) I dip one cup of cocoa water out before adding my food. I boil water in the morning for 2 cups of oatmeal and 2 of coffee…around 4 cups. This is roughly 2 liters per day of boiled water and comfort food…it is usually cooler in the ADK’s and the warm meals go a LONG way to making my spirits happy (even in the rain.) I carry about 1oz of aquamira in case there is something up with the water. In heavy 2-3 day rainstorms water can get a bit muddy, as an example. I use AM drops for this.

    The total weight for these components (not counting stove/fuel) is about 7-8oz (Opti-3.5oz, Bottles- 2.2oz, Platypus-~2oz.) AM supplies a good backup system. 1L water is enough to hike with (usually less after the first stop.) I carry about 1L less then I did before starting this system saving roughly a pound or so. I have been using this system since Steripen (or mOve) first offered UV systems in light weights. I think I gave away my old filter to someone many years ago. I use my pot (grease pot) to scoop water. BTW, The Opti fits into the older style Gatoraid bottles.

  3. Thanks Phil! I appreciate the post and all the great comments.
    What has me hanging onto my pump unit is the ease of just tossing one end into the water source and pumping away – no getting wet!
    I’ve picked up a sawyer mini and will fool around with the bag fill process and a scoop – great idea!
    The zip top bladders seem very convenient for filling instead of the tiny threaded end – I might just hack the end off an old sealed end bladder and see how that works rolling it down.

  4. I don’t mind using a pump. It’s a great opportunity for some contemplative time by moving water while attending to my water requirements. I use either an MSR pump with a handy tag-end pre-filter or a Katadyn pump with a bulb pre-filter. They work efficiently and without clogging. I don’t consider them much of a weight penalty. I use Aquamira drops as back-up. To me, sitting by the water is like sitting by a fire — the sights and sounds are restorative. I’m in no hurry in the woods and have no clock rushing me along, so to me, such camp chores are not a penalty, but an opportunity to be part of the natural process.

  5. Had a sawyer filter for a while. I considered it to be the worst product I had purchased for hiking. I could never get it to work properly. I had to exert way too much effort to get the water to pass through the filter.

    After using the sawyer and also using a pump filter for a few year I finally found the best solution. The MSR AutoFlow Gravity Filter is by far the best the best hiking/camping item I have.

    With a pump filter you get tired of pumping and only drink as much as you are willing to work.

    With the gravity filter you walk to water source, fill the bag, hang the bag and then start drinking. Very little effort. I have found that I stay hydrated better because it takes less effort to get the water.

  6. I have gone through several filtration setups. My latest version is a platty 2 litter hydration bladder with a sawyer mini spliced into the hose near the bag. Seams to work well.

  7. Question: is it the large dirty water platy that allows the Sawyer Mini to operate gravity style without squeezing the dirty water pouch to force the water thru the filter?

  8. Just wondering, but could anyone explain the advantages of these squeeze filters to an MSR MIOX ?

    I bought a MIOX years ago when I was a boy scout and the thing was winning all these innovation awards. I was out of the backpacking scene while I was in college, and now I’m getting back into it and it appears the MIOX is discontinued and everyone is using gravity filters or squeeze filters. Is there something wrong with the MIOX technology? Should I be looking at getting one of these other filters?

    I haven’t found any sort of explanation about why the MIOX was discontinued, so I just wanted to see if there was something that everyone else knew that I didn’t.

    • I never understood how they could give awards to a product at the beginning of the season when it only became available a week or two earlier. “They” still do it and it’s a headscratcher for me because I have the same access to early products as they do.

      I think MIOX went out of favor because it way to complicated to explain. Probably the same reason why AM isn’t that popular as the Sawyers. Didn’t MIOX also need a battery?

      • Yea the MIOX needs a battery, but it lasts for a pretty long time. I haven’t paid really close attention to how long they last, but if I were to guess, I’d say at least 10 days for two people. It is a bit complicated to use, but if used correctly it can kill pretty much everything. Also, filtering large amount of water is really easy with a MIOX, you can dose gallons of water in just a few minutes. Although, you could do the same with tablets I suppose.

        Anyways, these Sawyer filters look like a good bet and they are pretty reasonably priced and lightweight. I am starting to feel pretty tempted to switch over and put my MIOX in my at home natural disaster kit.

        • The MIOX generates chlorine dioxide and some other related chemicals, so it is roughly the same as Aqua Mira or Micropur tablets.

          I had a MIOX and found it fussy and unreliable. You have to do two or three steps exactly right, and you can run out of salt, need new batteries, etc. Aqua Mira is far simpler and lighter, too.

    • The MIOX is still an amazing way to treat water and it has advantages over AquaMira and other chemical solutions that few know about. It really isn’t that finicky. I’ve used mine for many years and it has never failed me.

      There are many advantages. For one, the fresher the chemical the more potent it is. As you use it, you essentially are creating a fresh chemical using salt and electrolysis. The cool thing about the MIOX is that the chemical produced is also completely safe to handle unlike chlorine dioxide tablets. The chemical it produces (hypochloric acid and chlorine along with many other oxidizing chemicals with very short half-lifes) not only treats the water but disinfects the container it’s put in. If anything MIOX was available way before it’s time and I believe we haven’t seen the last of this technology in the outdoor marketplace.

      The other thing I love about the MIOX is it can do large quantities of water very effectively. There really is no limit to the amount of chemical that can be created so if you need to treat water for a scout troop, etc., the MIOX is an excellent solution.

      MIOX leaves very little taste in the water, is easy to use (fill the small area with water and push a button…equivalent to about 10 drops), incredibly effective in eliminating everything from crypto to bad tastes/pesticides, light (about 2.5 oz with batteries), takes very little maintenance (batteries and salt), and is durable. About the batteries and salt…there is a battery indicator to let you know when they need to be changed (about once a season) and I always take an extra pair of CR123 batteries with me just in case. I also take a very small bag of salt as well (only takes a few pieces of rock salt to work).

      The disadvantage to any chemical treatment is that it won’t take out the ‘stuff’ in the water whether that be dirt or the microbes you are trying to kill. In other words, it doesn’t change the ‘aesthetics’ of the water. But there are many advantages as explained above. I even believe this is a much better solution than UV treatment due to the fact that it will work in murky water. I don’t know if you fully understand what an incredible piece of gear you own!

      MIOX was originally designed by DARPA, a department of the military that specializes in developing new, radical technologies. It was and is still being used by the military for many reasons, one of those being that it was the most effective solution for removing chemical agents from water (sarin gas, VX gas, etc.). It also could be used in the field anywhere military personnel were deployed in the world to effectively treat water for drinking. Keeping hydrated is one of the most important tasks taught to soldiers and the MIOX Purifier has done an excellent job in helping with this (I served for 14 years in the army). MIOX Corporation is located in Albuquerque, NM and this technology is revolutionizing the way swimming pools are treated, water is disinfected in commercial aircraft, and it is also being used in culinary water facilities. Currently MSR has developed a new MIOX unit to treat enough water to supply a family’s water needs in Africa, and the unit is the size of a half-gallon jug! You can search “MSR Global Health” to learn more…

      You should feel lucky to be one of the few who owns a MSR MIOX Purifier! It believe it’s the best chemical solution out there still.

  9. Marco’s comment is interesting. I’d never read anywhere that boiling could make some water worse. I was wondering why you bothered to filter water for cooking (eg, that you were going to boil)? I just dip my cook pot in the stream/lake and then heat it up. I also wondered why you would dump any leftover filtered water. Why not just drink it?

    You need to wait just as long for liquid AM to work as you do the tablets. In fact, technically the tablets should be faster since you don’t need to wait the 5 min after mixing A & B together (assuming you don’t pre-mix for a day’s worth – especially nice with a group). Oh, and FYI the drops do not kill crypto within 30 minutes. Both take up to 4 hours for that so if you’re taking from suspect sources you should wait longer.

    But as you found out, sometimes you get a bad batch of tablets. If you don’t see the tablets start bubbling immediately you know something is wrong. The liquids have a shelf life so I suspect those could go bad as well, but as long as the mix turns yellowish you have an indicator that it is working.

    • I don’t always filter water for cooking – sometime I just boil and do it that way too. I don’t drink all the leftover water in the morning because sometimes there is simply too much leftover and I’d rather not carry it.

      I’ve had a bad batch of Katadyn tablets, plus they generate trash. Liquid AM is just easier (for me) and has a shelf like of 5 years. As you say, you can see if it’s good when it turns yellow. I don’t have crypto where I hike, so I don’t need to wait 4 hours, but it’s moot since I only use AM overnight.

  10. I’ve just started using the Mini on a couple of trips and it’s one of my current favorite pieces of gear. Here in the PNW, where water is easy to find, I haven’t been carrying more than .5 ltr tops because I can stop and drink almost instantly at any water source. A 1/2 liter smart water bottle for walking and a 2 ltr reservoir for camp is all I have to carry – a huge weight saving! I’m switching from Aqua Mira, which I also like, but I’m really enjoying the time saving with the Mini.

  11. Some questions: (1) You say you use liquid Aqua Mira because “it works faster than tablets because it’s in a liquid solution,” but you appear to use this exclusively for overnight decontaminating. Why not use tablets since it is sitting overnight anyway? (2) It appears that the Platy is your dirty reservoir but the water inside it becomes clean overnight. Do you worry about contamination from the outside of the container and/or the threads when using the next morning? (3) Would you still recommend this system if you were hiking with a group and everyone was working together to carry group items, such as with a Boy Scout troop? As a BSA SM, I am trying to cut weight for backpacking trips, but some others are really attached to bringing a pump style filter. I really like the Sawyer Mini, and consider it one of the few “game changing” innovations in backpacking over the past couple of years.

    • Great questions:

      I use AM because I’ve purchased tablets that didn’t work in the past. There’s no way to tell if tablets are still good unless you dump them in water by which time it’s too late. You can see whether your AM is working in 5 minutes however, and if it works once, the entire bottle will work since it’s in liquid form. You could use solid tablets, but I won’t go near them anymore. I had a 120 tablet batch where 90 tablets were bad.

      2) Yes I do worry about contamination in the threads so I don’t ever put my mouth on them. It’s still safe to pour purified water form the platy into my drinking bottles since it doesn’t touch the threads and even if it did, since the water is chlorinated and disinfected, it will disinfect anything it touches. If you ever have to irrigate a wound,in the backcountry, chlorinated water is the way to go.

      3) Absolutely! You can rig up a couple of minis for a large group attached to large reservoirs and quickly purify water for your entire group. You still have to be careful about cross contamination, but you have same problem when you use a pump filter (touching the clean outflow with a dirty wet hand). I’d also recommend you look at the Platypus Gravityworks system which is better suited for large group use. It’s a very well thought out system and also very lightweight.

  12. I have a similar setup, using the Platy 3L Big Zip. some ultralighters complain about the extra weight of the clip closure part of this bladder, but I have found the weight inconsequential compared to the convenience of filling through the larger opening. I have not tried to use this as a traditional bladder – i.e carried in my pack, but just use it in the same way as Philip.

    BTW – I had an older version of the Big Zip and noticed a factory seam had started to open. I called Cascade designs, explained it was a much older version and was there a way I could repair it.. They said send it back and with in a week I had a brand new version in my mailbox. Nice customer service.

  13. How does the mini handle tea-coloured water? The main advantage I’ve found for my pump (MSR Miniworks EX) is that it is super easy to clean the filter when it slows down because it’s removing the tannins. Some of the lakes in these parks are dark like coffee, so easy cleaning is essential.

    • The mini comes with a syringe that you backwash it with. I just fill the syringe with filtered water. Usually one syringe worth is enough to clean the filter and return the filter’s flow rate. I wouldn’t leave home without the syringe as the water sources here in Arizona are often dirty. Once home, I backwash the filter several times then squeeze some water with chlorine bleach through before storing.

  14. We used a similar setup on the PCT last year – a “dirty” 3L platypus bag fed through an older sawyer gravity filter (circa 2012, purchased just before the squeeze began showing up on my radar). We both used platy big sips for treated water through the desert and plastic bottles from the Sierra north once water was a little more abundant. I spliced quick-connect fittings into the drink tubes just before the bite valve so we could hook them up to the output of the filter. Then, at lunch or at camp we hung the dirty bag and let it do its thing while we did ours. Carried aquamira as backup but never needed it; never had a puncture or filter failure. It was a great setup for two people hiking together and I’d use it again for sure. I’d consider moving to individual inline filters for a little less complexity, but they don’t play well with the beloved drink mixes.

  15. Why do you prefer Aquafina over other bottles?

  16. Guess I am old fashioned and careful. After two episodes of my body disliking Chemicals for Water Purification and the resulting Hospital visits, I’m sticking with my trusted and proven friend of hundreds of gallons of pure clean water,,my First Need Deluxe. You can count ounces etc. etc. but I’d rather carry the ounces than lose pounds the hard way. My backup is Chlor-Floc the military issue water purification system though a bit labor and time intentsive it has worked when I tested it out while car camping and out on the Lake in my Boat when I needed a water refill. I am always amazed at how much material the Chlor-Floc removes from a quart of water. Instead of Bottles I bought a Nalgen Bladder bag some time ago which holds two quarts and you can screw the First Need right to the bag for convienance. For occasional water bottle backups I prefer the Smart Water Bottles in the two liter size, they seem to last longer than most other bottles and resist cracking and breaking down longer is my experience with them. If I do not carry the Chlor-Floc as backup I carry one of the new “Straw” type units, which work very well but you cannot fill a bottle with water using them…

  17. I have used tablets for years, but am now going old school with household chlorine bleach. Two drops per liter in clear running water (drops, shake, drink). Believe that was how it was done before the days of the fancy filtration systems. After all, isn’t that what Aqua Mira is?

    • Chlorine (liquid bleach) and Chlorine Dioxide are very different. Chlorine dioxide is much more effective against Giardia and Crypto. Go to the CDC and EPA web sites to read more (where they say that bleach has a very low efficiacy at killing those organisms). There’s also no such thing as instaneous chemical purification (drops, shake, drink).

      • Thanks Philip! I had read an AT thru-hiker report where he used chlorine bleach on the last 1,000 miles and I know several backpackers that have used it for years and an old scout master from the 1940’s that used it as their main water treatment. I had no problems on a recent 3 day trip. But I dare say the CDC and EPA likely trump those sources. I may go back to my tablets.

  18. You should be aware that the new style filters (Sawyer and Gravity Works) lose effectiveness after freezing. If you even suspect it might dip below freezing, make sure you blow the water out (mouth on the clean end) and slip it into your bag/quilt.

  19. Hi Philip. I have been stalking you for a while, but this is my first post. I see the “Original Squeeze” in the second picture. A few questions….. 1) Is upgrading to the Mini worth it (other than the 1oz weight saving)? 2) Do the Platy bottles fit the Original the same as the Mini? 3) Is there a flow difference between the two? Thanks in advance! I really enjoy your blog.

    • The mini is a lot less expensive mainly and the flow rate is much better, in my experience at least. The platy bottles fit the same, but I always wrap mine in plumbers tape to get a tight fit and prevent cross contamination. Glad you’ve de-cloaked!

  20. We use a very similar hydration system, after years of working with pump filters. We have a 4L MSR Dromedary, which serves as the large reservoir for purifying water. Each of us uses a 2L Camelback bladder, or I sometimes use 1 or 2 Nalgene 1L Cantenes, for day use. We use Aqua Mira for purification, though I have used a Steri-Pen on a couple trips. The flow-through filters are intriguing though, if they deliver on the promise of rapid hands-off water filtration.

  21. I’m not sure where I found this information, years ago, but I’ve used it for years with no bad effects so far. It goes like this: for Aqua Mira, you can double the dose for half the time, or halve the dose for double the time to get the same sterilizing effect.

    Until the advent of the SteriPen and the Sawyer squeeze, I would sometimes use the double dose for half the time to prep water on trail to be drunk more quickly if I was thirsty and didn’t want to wait as long. But the more common use of this principle is to halve the usual dose for water I’m treating overnight (like Philip does). Over a long trip, this can save you quite a bit of AM and stretch out your supply for a few more days.

    My current system is to use AM in camp for large volumes of water I’ll use at breakfast and to start hiking with the next day, and to use the Sawyer Mini to camel up at water sources on trail, so that I can drink my fill right away and carry less water. When temps are below freezing, I’ll usually use a SteriPen for this so that I don’t have to worry about the Sawyer freezing. At dinner time, I’ll often just fill my pot at the water source (if it’s close enough to camp) and boil the water (which I needed anyway for my hot beverage and meal).

  22. Very interesting post; thank you very much.
    I use a steripen; it is light and easy to use. I carry a few purification tablets for emergencies but so far am glad I have never had to use them. Why go out into the wild and then dose yourself with noxious industrial chemicals? Daft
    I have a katadyn mini filter but have found it unsatisfactory.. hard work, slow, prone to blockage. I will try the sawyer squeeze, although I see they cost double what you pay, here in England. Filters do have the advantage of actually removing bad stuff, rather than just killing it and then letting you drink it as the steripen does.
    Though I wish I knew where the filter puts the bad stuff having removed it.. I also wish I knew exactly how the steripen works and how effective it really is, as opposed to how effective it says it is.. still, fingers crossed it has worked for me so far!
    Here in Europe it is not usually necessary to filter water from springs or from glaciers.. most contamination seems to come from grazing animals of one sort or another

    • The UV light produced by the Steripen doesn’t actually kill the critters. It makes them unable to reproduce. So, you are drinking the live critters that will soon die without offspring. The reproduction in your body is what makes the critters dangerous so this is safe.

  23. Used Aqua Mira for years as hated every filter I tried until the Sawyer. Those that have had problems with it (me included) didnt read the directions. Primarily after using it when you get home you have to clean it, otherwise it gets all plugged up as it dries. If you clean before you go and after you return there is zero issue and it totally changes how you hike. No waiting, no pumping, instant water anytime any place. Oh, and why are you treating and filtering cooking water? If its getting to at least 160-170 degrees youa re killing everything anyways so wasted effort.

  24. I forgot one more thing….while Steripens are nice ANYTHING that uses a battery will eventually fail. Period.

    • As will you.. or any squeezy thing.. or any filter. What’s your point? All equipment needs care

      • Even Aqua Mira drops can freeze if it gets cold enough, splitting the sides of their container, to dribble out once thawed. Just like with a filter, in winter it’s best to keep your AM in your sleeping bag or pocket to prevent this. I’ve had this happen only once to me, but lesson learned. Another reason to have a backup method.

  25. I’ve seen people say to get in the spirit of ultralight by removing the little bands off the water bottles, right under the lids. I see you haven’t done that and I’m glad. Here’s why: back home, I have several reusable water bottles of different brands, different volumes, different mouth sizes, etc. The bands help me match the bottles to the lids, by color, much more quickly and efficiently than if I had to just eyeball them.

  26. I’m really sad they stopped making Polar Pure. It’s a small bottle with iodine crystals that allow you to make iodine solution as you go. Because it’s already in solution you don’t have to use as much as the iodine tablets and you call pull all the treat less/wait longer tricks that people are talking about with AM.

    The big win though is that you don’t have to wait 5 min before dumping everything in the bottle and taking to the trail again. I’ve used it on training trips with SAR groups where I just step out of line, fill and join the group at the end of the line without anyone else having to stop. I’m going to be really sad when I eventually lose mine.

    They stopped making them because people were pulling the iodine out to use for making meth. Dumb reason, but so it goes.

    Thanks for posting about all the alternatives. I’ll have to try them eventually if I don’t just go to drinking almost everything straight. :)

    • California Girl

      Iodine doesn’t work really well against giardia and does nothing against crypto, plus long term use is discouraged. It’s also dangerous to pregnant women. It used to be CDC’s recommended emergency water treatment but has been removed from their recommendations as well (replaced by chlorine treatment). There are backpackers who have developed serious, severe iodine allergies resulting in needing to avoid iodized salt, seaweed and any other food or additive containing iodine, or have disastrous results.

  27. Kurt in Colorado

    I use the MSR GravityWorks 4L bag, and frequently have issues with airlock: if there are air bubbles in the membrane filter, it will not allow water to flow. No amount of forcing will overcome it. It must be backflushed.

    Since the Sawyer is also a membrane filter, I am curious how many people have trouble with it being airlocked? Does it ever stop flowing? Don’t you have to backflush it to get rid of the air bubbles? I would switch to a Sawyer, but I worry that people are overstating its ease of use.

    I should note that the MSR Gravity filter can airlock even while trying to filter clean tap water at my sink. It’s not “dirt” that clogs it, it’s air bubbles. I’m not sure everyeone understands that about membrane filters? Or maybe someone more knowledgeable can enlighten me.

  28. My buddy and I bought Platypus Gravity works this summer for bicycling in Idaho on the hot springs route and we both had zero problems and water to spare in minutes…the system is fast. Lift the lower bag above the upper once it gets a little lean water to begin the process to clear the air in the filter and line. Then the system runs fast. No issues, no plugging and quality bladders and great bite valves all the way. And the water was sooooo gooood. No chemicals.

    Yep a little more weight but worth it in my book. Like all systems it takes understanding but once you get it your water worries are over.

    Don’t let the filter freeze, blow it out after you use it.

    Bill in Tomahawk, Wisconsin

  29. Hi all,
    I pump water then steri pen, fast never been sick and can use really lousy water supply if that’s it. Always carry chemical back up and give water an extra rolling bit of boil when cooking.

  30. Jim – which steripen do you use?

    • Hi John,
      My SteriPEN is the adventurer Opti. I’ve had it around 3 years and battery life handles the needs of 1 and 2 person trips for 3 days maybe 4.
      One note. It takes 2 CR 123 batteries and if you’re trying to pick some up at the little store half way up the mountain you may not find them or you’ll be shocked at the cost. Get them in town and in a value pack.
      Good luck,

  31. Thanks for the tip on using plumber’s tape for a good seal between the Mini and Platy Hoser. I tried it at home and it works great! I like the Platy much better than Sawyer or Evernew bags because of the soft material and ability to hang the bladder for gravity filtration, but was having difficulty getting a good seal.

  32. Had the Katadyn pump filter for canoe camping. After a couple backpacking trips, we bought the Sawyer Mini…..but (for two people) I was driving myself insane squeezing the bag! We are on the prowl for an easier way for an upcoming long distance hike (and for an AT thru hike planned for next year), when I see (angels singing) that you don’t have to squeeze?!? Gonna dig out our Mini right now and try the gravity thing. If it works (cue another alleluia chorus), we may just buy a second Mini and save ounces and bucks. Oh…and toss in a bottle of AM for good measure. :) thanks!!!!

  33. I built a gravity system by attaching some IV tubing between the Sawyer and via that Sawyer and my Evernew 2L bag via that threaded ends set Sawyer sells.

    I just fill the bag, hang it from a branch and kick back and let gravity do the work. No more squeezing. No more wet knees.

  34. N/M lol, I see it in the pic. What does MYOG stand for?

    For those talking about flow the regular Sawyer is better.

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