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MSR MiniWorks Ex Water Filter
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105 Reviews
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Keep your water clean for years.
Filter your water year after year with the MSR MiniWorks Ex Water Filter. Clean this lightweight, compact filter back to like-new condition, without any disassembly tools. The MiniWorks' ceramic element ensures long-lasting protection against bacteria, protozoa (including crypto and giardia), and particulate, and the carbon core removes yucky tastes. MSR's little wonder (7.5 x 2.75in) can filter up to 1 liter per minute. As a bonus, the MiniWorks Ex Water Filter screws onto a standard Nalgene bottle or any MSR dromedary bag.
- MSR's best-selling micrfilter known by backpackers for longevity
- Marathon EX carbon/ceramic element ensures clean, tasty water
- AirSpring Accumulator delivers one liter of water per minute
- Field cleanable without any tools
- Includes filter, hoses, stuff sack, hose float, scrub pad, and instructions
- Item #CAS0479
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Great filter for small backpacking crew
- Familiarity: I've used it several times
Filter works great for a small backpacking crew (3-4 people). The ceramic element needs to be cleaned frequently depending on the quality of the water being filtered. Used this one for the first time in the Linville Gorge and had to clean the element about every 8 liters or so to maintain efficiency. Overall a good quality filter.
Perfect for 2-3 day Hikes
- Familiarity: I've used it several times
The water was quite clean to begin with,
The unit clogs and you have to scrub the ceramic unit with the supplied green pad. It will start working again, but slows down again after a few liters of water. It is physically demanding to use. Not hard, but if you're supplying water to two people on a backpacking trip your arms are going to get a workout along with your legs.
Jean VandekieftGearheadPerfect fit on Nalgene
- Familiarity: I've used it once or twice and have initial impressions
This is the most efficient water filter if you are doing some backpacking and have a nalgene with you. It screws right onto it and the filtering is fast enough and tastes fresh. This is also very light and perfect for a long backpacking trip
Absolute garbage
- Familiarity: I've put it through the wringer
I do not know if I had a faulty unit. However, I do not know who thinks there is a strong business case for a backcountry water filter that filters water at a rate of 1 liter per 20 minutes. I tried this pump for the first time in the Olympic national park, where we were planning to cover 12-20 miles per day. When you are trying to cover that distance every minute in the wild counts. However, we literally wasted 2 hours a day filtering water :S. I am not a newbie, and I used to love the MSR HyperFlow Microfilter, before deciding to try this new pump. My mistake was not to test the pump before hitting the backcountry. The situation got so bad on time spent to pump water that we had to start rationing water in a place where there is water available every single step of the way. That said - AVOID THIS PRODUCT! (in picture - my gf resigned to having to spent 40 mins to pump 2 liters of water in the final day of the trip)
Always Keep Handy
- Familiarity: I've used it several times
I got to use this a lot this past summer on my road trip out west and really loved it. Not a very large system but works perfect when I need to refill my 48oz nalgene. I love that it can screw right on to my water batter, there's no need for another piece to make it functional.
Looking forward to more adventures and this filter is something I will always carry with me.
Umm...say what?
I openly admit I have not purchased one of these particular filters yet. However, I do know a bit about water chemistry, and I can assure you that there is no amount of scrubbing that will return a carbon core filter "back to like-new condition". The carbon is the part that absorbs odors and gasses, and also some of the potentially harmful dissolved minerals, and once those are attached to the carbon it cannot be "cleaned". I'm sure the system works just fine and that it will remove bacteria and other harmful microorganisms almost indefinitely with proper care, but it will never again be "like new".
Clean Agua
- Familiarity: I've used it several times
This is a fantastic option for a water filtration system. It is small and compact but you can really crank out a decent amount of purified water pretty quickly. I love the fact that this will screw directly onto a wide mouth bottle. This is perfect for backpacking trips in the backcountry.
Samuel NicholsGearheadInitial impressions are pretty good.
- Familiarity: I've used it several times
I've done a few hiking trips with this filter and I really like it, the more I use I the more I like it.
The water I've filtered has tasted great and I've had no ill effects from it.
I find the pump rate acceptable and only slows when filtering water with a lot of sediment.
I like the fact it screws directly onto the Nalgene bottles and the clean outlet from the filter is mostly kept protected from any exterior contaminants. It does seem like they put some thought into how the filter will be used and how to design it so to minimize contamination risk from unfiltered water.
I do worry about cracking the cermanic filter from something like a fall or dropping it but you could carry a spare filter.
The filter itself is heavy but overall I don't see it as excessive...I could shed a few lbs to make up for the extra weight of the filter.
I'd seriously consider buying this again but I know filter technology is always progressing but I do rate this filter highly, four star in fact. I dropped one star for the weight and the concern about breaking the ceramic filter so if that doesn't bother you then boost it to 5 stars.
Great Purchase
- Familiarity: I've used it several times
Started backpacking within the last year and upon picking up gear majority of veteran hikers recommended this. I ignored their advice & instead purchased the Sawyer MINI for easy storage/weight. With EPA water regulations going down the tube, I decided to make an upgrade & purchase the MSR mini. Not yet being on a trip to use it, I've tested/experimented/played with it numerous times to prepare myself for field use. It's simple. It works. And it's great! Plus young kids love watching/learning how it works. Just follow the elementary school type instructions for cleaning & care, it'll last for yrs to come.
Cons-weight & size for minimalists, &
$ (for some people)
Pros- There's a reason it hasn't changed much in design/$ since '97...bc it works perfectly & one of the best filters recommended out there
Tested True
- Familiarity: I've used it once or twice and have initial impressions
Picked this little bugger up for a 3 day trek through Colorado with Fjallraven, but they ended up giving us a Grayl water filter bottle so didn't get a chance to really put it to the test. Initial testing was great, easy to use, adequate speed of filtering and taste was good. Looking forward to putting it more to the test on the Sky Rim Loop in Wyoming later this summer.
Kyle LaudenslagerGearheadQuality Filter - Last for years
- Familiarity: I've put it through the wringer
I have had this filter for over 10 years now. This filter won't let you down even if your water source is highly silted. It works great and if the flow ever slows down you just give the filter element a light scrub and its back to top form. I've used it in many environments from high alpine, to rivers to desert potholes.
Clean water, and convenient
- Familiarity: I've used it once or twice and have initial impressions
Does a great job of filtering, and is not super heavy so is great for backpack trips when weight is the main concern.
One of the best water pumps out there
- Familiarity: I've put it through the wringer
This has been my families go to pump for backpacking for at least 10 years. Works extremely well and it's really nice that it works with any water bottle with a Mouth like a Nalgene bottle. Personally I hate using steri pens and tablets. I know steri pens work, but I don't trust them as much and tablets leave a taste no matter what anyone says. That and with those options you're still going to have some grit left in your water. I would recommend carrying an extra ceramic filter that goes inside when you're going well out of the way. My brother was cleaning it once and managed to drop and break it rendering the pump pretty much useless. Luckily we had an extra.
MSR Quality
- Familiarity: I've put it through the wringer
MSR has the rep that it has for a reason. There aren't many times when you would reach for a water filter and can afford to have it not work, which is why I always reach for my MSR. It just works and I know every time I need it, it will do its job.
ForrestGearheadHave older model for 10 years now.
I can't seem to understand some of the reviewers out there.
Can't clean it without a sink!
Lost the cleaning pad!
It's to slow!
Did your mother drop you on your head when you were a baby?
Do us all a favor and stay home, you clearly don't belong alone in the woods!
I don't need another rescue mission cause you didn't bring enough hand lotion to make it back without chapped hands.
This filter is perfection personified.
Works all the time. Can be cleaned in a lake, pond or a puddle.
Yes I've done all three.
Was able to get water from a trickle between rocks to keep me fed and hydrated.
But wait, It doesn't fit my camel back reservoir. Ahh, would you like me to carry your water for you next time?
What a bunch of wimps. This pump is adaptable to get water from any where and put it into any container and only takes common sense to do it.
Buy this, you won't be sorry. I read the new ones pump a liter a minute, mine is about 5 minutes. Still not bad for taking something that a creature shat in and being able to drink it with no after effects.
And NO, I don't work for MSR.
Happy Trails.
Backpacking not recomended
- Familiarity: I've used it several times
Worst back country crap of all time it needs apparently a sink or specific wash basin to clean the filter every time you use it works only when your near a steady stream of water if its stagnant forget even getting your nalgene filled. alll in all if your car camping great if not heavy piece of useless equipment.
I'm afraid I had a similar bad experience.. Purchased new with my REI divided to replace my PUR water filter, which I've never had any problems with. Stopped working after 6 liters pumped. Took it apart very very carefully and read the manual. Had my mechanical friend do the same without any input for me to see if we'd get a different result and we didn't. Simply wouldn't work on day 3 of a 9 day back country trip. Based on all the positive reviews assume it was just a defective pump, or there is always the possibility of operator error ;-) But we did work on it for some time. Luckly we had a back up as we certainly didn't have enough fuel to boil 6 days worth of water consumption.
Great for frequent backcountry travelers
- Familiarity: I've used it several times
MSR Miniworks EX is a long-lasting filter with the added benefit of cleaning chemicals and pesticides from water. It is on the heavy side for a hiker, and requires slightly more time and force to pump than any of the other pump filters. However, it treats more than twice as much water as any of the other pumps, treating 2000 liters before a replacement cartridge is needed. A long-lasting ceramic filter, the Miniworks is a good choice
My brother has had MSR filter system for years and they work great in general. However, on most recent on he purchased, there was no feature to keep the pin in place on the pump arm, and as a result it got away from us in a lake at Glacier NP and we had to improvise with sticks for a couple of days... Does the pin on this particular model click into place like the older ones?
Let the good in, keep the bad out
This is a great filtration system. The water comes out clear and tasty. It's small and lightweight so great for packing into the bush. The fact that it screws onto a Nalgene is an example of design for use and took some forethought for sure.
Works Great
- Familiarity: I've used it once or twice and have initial impressions
This thing is super simple to figure out and works great. I have only used it once, but it was really handy to have it on a yurt backpacking trip we were recently on. We simply gathered snow and pumped our fresh mountain water. Sure as heck beats carrying a bunch of water through the snow for 6 miles. Highly recommend from initial use! Will use it on a Grand Canyon trip coming up so I'll update you on how it goes!
sweet
This filter works great. It’s very user-friendly: easy to set up, easy to clean, easy to take apart and pack. It fits on most water bottles or bladders and is perfect for any hiking adventure.
After reading the reviews, I'm convinced this is a high quality, durable filter. I first encountered this filter when hiking in Nepal with some Finnish friends. They used the filter, then used a UV filter on that water. I didn't exactly understand why; something about the MSR being able to filter out something, and the UV being able to filter out something else.
I would like to ask you guys if this MSR filter is sufficient for pretty nasty water that may have giardia inducing parasites, etc.? Or do you typically use this filter COMBINED with another purifying device like UV or drops?
I understand that it probably depends on the water source, but thanks for any help.
Jared DownsGearheadHey Max,
So this is a great filter. I've had this filter since around 2008 and as long as I clean the filter and store it properly after each use, it will continue to last me for years to come.
It has an inner charcoal filter (for tastes and odors) and an other ceramic filter that filters out particles above 0.2 microns in size. So that is almost everything. The one thing this does not filter out are viruses. This is why you saw those people using the UV light (most likely a SteriPen) as a final step to kill any viruses that could be in the water source. Personally I'm not a huge fan on the UV pens as they do not kill everything in the water as there are certain parts of the water that do not come in contact with the UV light.
An alternative to the UV lights (SteriPens) are tablets such as (Item # CAS0775). The tablets meet EPA purifier standards for the neutralization of viruses, protozoa, bacteria and giardia cysts. So those will work great for treating your water. Only down fall is there is a 30 minute wait time after putting the tablets in the water and then there can be a bit of an odd taste to the water.
Shoot me an email if you have any questions at all!
Jared D.
Expert Gearhead
801.736.4336
jdowns@backcountry.com
I bought one of these a while back and struggled to get it to pump any water through. Not sure if there is a manufactured defect or if I failed to prime it correctly. The priming instructions that come with it are a bit vague. Any tips/more detailed instructions on how to go about priming it correctly and what I should be looking for to determine if I primed it correctly? Thanks.
Karen, I just came in to post a review and this was going to be a point I would make. I had the same difficulty, except it was after I had initially used it at home. It worked great at home and for a few liters in the backcountry, then became frustrating as I couldn't get much water through it.
It turns out that after my first use at home, I should have used the green pad with water on the ceramic filter after flushing it clean for the first time. I guess it was dirty, not from water, but maybe dust or w/e during the manufacturing of the ceramic disk. Now it seems to work properly, but only time will tell.
How do these filters work with sea...
How do these filters work with sea water?
No, unfortunately it will not. The ceramic element is so molecularly "huge" compared to even viruses that it will most definitely not remove sodium ions, which are wayyyy smaller. The carbon filter may help with a lot of solids and even some minerals, but once things are well dissolved in water, the carbon won't do much.
Bottom line, it will be good for gargling but not drinking.
You would need a desalinator to make it drinkable, and those will run you ~250 to upwards of 2,000. (google Katadyn Survivor 35 and 06).
would this be good for unsafe drinking...
would this be good for unsafe drinking water in Nigeria?
The only problem is that this (and nearly all) filters are not effective against waterborne viruses, which may be of concern in untreated water in undeveloped countries. It would be a great first step, but you are probably well-advised to treat the water for viruses as well, after its been through the MiniWorks. A UV treatment or some sodium chloride drops/tablets would get you really in the clear.
This FILTER filters out many things including bacteria. But if you have things like virus in your water source, you would be better off buying a water PURIFIER which can be found sold alongside many FILTERS. They are somewhat more expensive but if you are in an area where the water in your environment is so contaminated; I would go for a PURIFIER instead of a mere FILTER.
http://www.rei.com/learn/expert-advice/water-treatment-backcountry.html This article will be very helpful in understanding the difference between filters and purifiers.
How do you order new ceramic filters for...
How do you order new ceramic filters for this item? can you use the one for the other filter's?
Geoff ConnerGearheadWe sell the ceramic filters, item #CAS0484.
Debating between this and an MSR AutoFlow...
Debating between this and an MSR AutoFlow (which sounds like it's 2.2oz lighter, will be more friendly to the group, and faster but potentially less versatile and more of a pain in the ass to maintain) for an upcoming 9 day AT trip. Any other advantages/disadvantages I'm missing?
Big question I have w/ the MiniWorks is connections to my water storage. I'm planning to take a 2L Osprey HydroForm bladder and a couple of 1L Platypus soft bottles for electrolyte drink and temporary water storage and transport at camp. Does the included interface screw onto an Osprey bladder? I believe it's made by Nalgene. If not, can anyone recommend bladder tubing that will definitely fit the nipple on the clean side cap?
Hi Sid,
The AutoFlow is more of a camp type of filter system than one for the trail (see some of the photos of it in use below). That's not to say that it wouldn't work (especially if you're filtering for the whole group at once as you travel), just that the MiniWorks is more suited to just getting to pumping water on the fly. The Autoflow needs to hang or be held up...dependent on gravity, not mechanics.
Either of the MSR filters use 3/8" tubing. So does the Hydroform. A couple of sets of quick connect fittings strategically placed in the
lines should give you full compatibility with any of the systems you mentioned. hope this helped.
Very helpful Phil! I'm progressively leaning towards the MiniWorks for the durability and flexibility, speed/multi-tasking be damned.
Should these 2 bits let me mount a small section of tubing w/ the male bit of the quick connect kit semi-permanently to the nipple so I can still fill stuff w/ the right threading and use the other section of the tubing w/ the female end of the quick connect for filling narrow mouth bottles/other bladders/etc?
http://www.backcountry.com/camelbak-pureflow-replacement-tube
http://www.backcountry.com/camelbak-quick-link-conversion-kit
I got the MSR replacement hose. This fits on the clean end nipple and you can use it to fill the platypus bottles. The Hydraform's cap is too big for the filter, but the hose works just fine. I have had this filter for years with no issues.
does this pump come with an additional...
does this pump come with an additional house for the output nozzle? i know some filters (katadyn vario) come with another hose to help fill up reservoirs. i usually hike with a camelbak 3 liter bladder. if it doesn't, is it a problem that can be solved by running to your local hardware store for a tube?
No it does not come with one, input hose and the standard wide mouth nalgene size output
The MSR replacement hose will work fine. I use it to fill up other bottles besides a Nalgene.
does this pump come with an additional...
does this pump come with an additional house for the output nozzle? i know some filters (katadyn vario) come with another hose to help fill up reservoirs. i usually hike with a camelbak 3 liter bladder. if it doesn't, is it a problem that can be solved by running to your local hardware store for a tube?
Hey there, this filter doesn't come with an extra hose, I am not sure if a water bladder hose will fit to the nipple/output on the bottom or not... MSR says this on how to filter water:
Place a clean container under the filter OR attach an MSR® Dromedary Bag onto the bottom of the filter...
So basically a water bottle or MSR's specific water bladders...
I personally use the Katadyn Vario for all general needs and just pull the bite piece from my water bladder, insert this into the bottom of the Vario and then fill the bladder while its still in my pack...
I use the Katadyn pocket for the nastiest water and then a Steripen when I know the water is clear...
I'm looking for a clean side cap replacement....
I'm looking for a clean side cap replacement. Where can I find one?
available from MSR's website
http://cascadedesigns.com/msr/water-treatment-and-hydration/water-treatment-and-hydration-accessories/miniworks-cleanside-cover-w/-gauge/product
Is there anyway to make my miniworks pump...
Is there anyway to make my miniworks pump faster/more efficiently? when I pump, the amount of water that comes in doesn't even fill the chamber. It pumped much more efficiently when I first purchased it.
It's a ceramic filter so you might try cleaning it out if you have never done so. It traps all the grime and cuts down on water flow. I clean mine after every trip, but thats probably a little excessive
I clean mine after every trip too. The part that I question is why the chamber that feeds into the filter doesn't fill completely.
Use the silicone lubricant in the maintenance kit to keep the rubber o-ring sealed more tightly to the chamber walls. It should be applied when you clean it after each trip. Replace the o-ring if that doesn't help.
Also, when pumping I like to pinch the hose against the housing on the inward push to help force the water down through the ceramic filter instead of letting it escape back out the hose.
I have found after pumping in pout your finger over the plastic piece were the hose and filter meet and that makes shear that all the water is pumped through the filter and not tout the hose agen.
I have found after pumping in pout your finger over the plastic piece were the hose and filter meet and that makes shear that all the water is pumped through the filter and not tout the hose age.
Are the threads compatible with standard...
Are the threads compatible with standard bicycle bottle threads? (Camelback Podium style?)
All water bottles have slightly different threads. I doubt these would be the same.
does this one fit on the kleen kanteen...
does this one fit on the kleen kanteen bottles ?
Yes, but only on the wide-mouth models with the cap that fits outside the threads.
I've noticed it fits well onto my Sigg wide mouth bottles
I have been using this water filter for...
I have been using this water filter for several month now but have not tried on any real unusual sources. I will be shipped off to Afghanistan soon and would like to know.
Do I still need to carry iodine tabs then filter the treated water?
I hate the taste of those tabs, so I am wondering will it pull the taste out?
Or do I not need them at all?
Any help would be greatly appreciated.
-Charley
If you're going with the US military, you don't need either one. Water bulls are everywhere.
In any event you don't generally need to treat water before you filter it. You use either the tablets or the filter.
I dont think you need iodine tabs. I use it to filtter brown and green water from the jordan river and the water go ut clean!
I'm planning a multiday backpacking trip...
I'm planning a multiday backpacking trip in October for Sipsy Forrest in Alabama and plan to take many more trips within the USA for years to come I'm considering this water filter as well as the MSR mini works. I recently saw both of these in person at an outdoor store. It seemed as though the Miniworks removes the most, yet it still doesn't remove viruses. Should this be of any concern for me in the USA? How can I combat viruses if so? Filter, then boil? I appreciate any input anybody has!!!
Viruses are usually not found in backcountry water sources in the US though they are not nonexistant. So chances are you could could probably use the Miniworks or another filter for years and never have a problem but it is always a possibility. Viruses are killed by just about any means other than just a filter. Some of the different means are: boiling, chlorine or iodine, mixed oxidants, purifiers and UV light.
So for your situation if you wanted to get a filter like the Miniworks you could pair it with chlorine or iodine for a good effectiveness. I personally wouldn't recommend using boiling to kill viruses just because I'd rather prefer a method that I can use to kill viruses without having to stop and get out the stove and boil water. While looking at the MSR website too, they make the SweetWater which does cover everything including viruses and is actually a hair lighter than the Miniworks EX.
I generally use the MSR Miox just because thats what I own and learned to use but I have used some of the other MSR water treatment devices so I would recommend any of them for you. Like I said too, you would probably be fine with the MiniWorks but if you ever plan to go outside the US or just want the peace of mind you might try combining it with another form or getting a different water treament device.
i've been doing quite a bit of digging...
i've been doing quite a bit of digging around for a water filter that i can depend on. I have been running into the term 'microns' quite a bit. I am doing an Isle Royale trip in a few weeks and am wondering if this filter will be okay to use by its self. On there DNR site it says a filter should filter .4microns or less for bacteria and 25 microns or less for tapeworm. Will this filter do the job?
On MSR's Site they claim it'll filter down to .2 microns... so you should be in business.
http://www.cascadedesigns.com/msr/water-treatment-and-hydration/expedition-water-treatment-and-hydration/miniworks-ex-microfilter/product
I purchased this filter in December, I...
I purchased this filter in December, I recently used it on a back country canoe trip in the Adirondack's, it worked great for the first couple of days, and then the steady stream of water turned into steady drops, and when I went to take it apart to examine it, it released a large amount of vapor build up. What is the problem?
It's working exactly as it should! That's the good news. Often what is looked at as a disadvantage to many filters is really the key to having a filter work properly. Because the filter element is taking very small stuff out of the water, the pumping action gets harder and harder. The reasons for this is that there are very small, microscopic voids that trap these small microbes that can make you sick (think shoving a basketball through a chain link fence). By default these objects also clog the small passageways that the water needs to get to your bottle. As a result you get a slower filter.
But because you bought the MiniWorks EX, you're in luck:). All you have to do is simply clean the filter element by, first, taking a good hold of it (if you drop this element on something hard, it will shatter like a porcelain doll). Next take the green bristle pad and lightly scrub it completely. This should only take a few minutes and only a very light scrub is needed. The last step is to re-install the filter element and start filtering away. You should notice a huge difference in the volume of water coming out of the hose. In fact, it should perform as it did when you first bought it.
The pressure release you experienced is simply the pressure built up while you pumped it. The MiniWorks EX operates using this pressure to force the water through the element. This is known as the 'Airspring Accumulator' molded to the outside of the body of the filter. This is what allows the MiniWorks EX to be the fastest ceramic filter on the market currently. No need to worry about the pressure...
I've got a barely used older model (blue...
I've got a barely used older model (blue top) that I'd like to dust off and use again. Are the new replacement parts (orings) and filter compatible with the old model?
Yes they are. Actually the new MiniWorks EX filter element will increase the speed of the old Miniworks by 20%.
What would water filter/purifier would be...
What would water filter/purifier would be ideal for international travel. I need one that i can use in pretty nasty water.
any of the msr filters are excellent. i use the sweetwater because it's pretty light and filters nasty water no problem. they are also easily servicable in the field.
Agree with Gabe- MSR makes first rate filters. However, internationally, viruses become a greater concern, and simple filtration won't do the job of removing them. You're then talking about purification. Boiling, chemical, or UV treatment is the only way to go. SteriPen or Miox (with extra batteries), and chlorine dioxide (MicroPur tablets) is what I would be bringing along.
When I look at the actual ceramic part,...
When I look at the actual ceramic part, if there are a few small black specks does that mean I have stuff growing and should replace?
No need to worry about the black specs. The ceramic element will accumulate foreign particles from time to time. If you're still concerned, follow the cleaning instructions in your owners manual. Remember it's better you're seeing these specs than not. At least they're on the outside. Here's the owner's manual just in case you don't have one:
http://media.cascadedesigns.com/pdf/msr_miniworks_ex_manual_en.pdf
Hello. How do I clean the ceramic filter...
Hello. How do I clean the ceramic filter thoroughly? I alaready cleaned the outside of the ceramic, but water flow is still low? Is there a type of soap that might clean out organic plugging or loosen silt? I have taken care of it. In silty conditions we leave the unfiltered water out overnight so the silt settles. Thanks for any ideas. Brad
You only clean the outside of the filter, and only use clean water to do so. Soap is a cloggy substance and will be unforgiving to the carbon granules inside the element. The filter is designed to last between 1000L - 2000L (264 - 528 gallons) of use. If your usage is less than this range, you might want to clean other parts of the pump to see if that will give you any improved water flow:
http://media.cascadedesigns.com/pdf/msr_miniworks_ex_manual_en.pdf
If the duck bill valve gets silt in it, you'll loose the back pressure causing the slow fill. Keep a bandanna around the in take to prevent silting. Found this out five days in canyon lands.
Wow man, I have used this same model for years and loved it. Always had good results from it. If it is BRAND new, then it is best to scrub the ceramic element first to ensure the best flow, but even then you can scrub it in your water source. Only when you are storing it away do you need to boil it or care for it.
I do NOT work for MSR, I am a youth pastor and a lover of backpacking.
Maybe you had a faulty one.
Hope your other trips are more successful!