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Reviews > Water Treatment > Filters > MSR Hyperflow Filter > Test Report by Greg McDonald


INITIAL REPORT - March 24, 2009
FIELD REPORT - June 02, 2009
LONG TERM REPORT - August 04, 2009


NAME: Greg McDonald
EMAIL: gdm320 AT yahoo DOT com
AGE: 22
LOCATION: Boynton Beach, Florida
HEIGHT: 6' 0" (1.83 m)
WEIGHT: 225 lb (102.00 kg)

I have been camping for 17 years, 12 of them have been spent hiking in the backcountry. My hikes are almost exclusively in Florida and generally range between one and three nights. My all-time favorite hike was a 10 day expedition in the Philmont Scout Ranch in Cimarron, New Mexico. I consider myself a lightweight but comfortably equipped hiker, with a pack averaging between 25 and 30 lb (11 and 14 kg).

Mountain Safety Research


Product Information & Specifications

MSR HyperFlow MicrofilterManufacturer: Mountain Safety Research (MSR)
Model: HyperFlow Microfilter
Year of Manufacture: 2009
Manufacturer's Website:
MSRP: US $99.95

Filter Element: Hollow Fiber
Filter Element Pore Size: 0.2 microns
Removes bacteria and protozoan cysts
Flow Rate: 3L per minute (Depending on water quality and conditions)
Rated Filter Life: 1,000L (Depending on water quality and conditions)

Listed Weight (Filter): 7.4 oz (209 g) [Verified Accurate]
Listed Weight (Packed Kit): 10.2 oz (289 g)
Measured Weight (Packed Kit): 10.4 oz (294 g)
Measured Weight Breakdown:
Pump: 4.9 oz (140 g)
Intake Tubing: 1.9 oz (55 g)
Pre-Filter: 0.6 oz (17 g)
Attachment Cap: 1.3 oz (36 g)
Stuff Sack: 1.7 oz (47 g)

Product in Depth

The MSR HyperFlow Microfilter is a water treatment system from MSR's "Fast and Light" series. It is one of MSR's newest models, designed to be more compact and lightweight than the MiniWorks series of filters.

HyperFlow Kit
HyperFlow Components

The photo above shows all the components that comprise the filter system. The pre-filter is at the top, immediately below it is the attachment cap, below which is the filter pump itself. To the right the filter pump and attachment cap is the intake tubing and at the bottom of the photo is the included stuff sack. The photo below shows the HyperFlow components properly put together.

HyperFlow Filter & Attachment Cap
HyperFlow Assembled

The filter media is an interesting design new to MSR. MSR calls it "Hollow Fiber Technology" but I had quite a bit of trouble finding information on it. I e-mailed MSR customer service to see if they could point me in the right direction and they promptly responded with all the information I wanted. What I learned is that the filter is basically a jumble of fibers "glued" (as it is described by MSR) into place. As the raw water passes through the jumble of fibers the fibers filter out 99.9% of all the bacteria and protozoa that flows past. The way that I've visualized it is coffee grounds being caught by the coffee filter (for lack of a better visualization).

Early Impressions

The HyperFlow arrived with some assembly required, but it was a small task for me since there really isn't a whole heck of a lot to it. One end of the tubing goes into the inlet on the pump while the other end is attached to the outlet on the pre-filter.

I was immediately pleased with the size and weight of the filter. Having said that I do think that the manufacturer's statement about the weight of the HyperFlow is a tad bit misleading. My measurements verified that the pump, pre-filter, and tubing weigh in at 7.4 oz (209 g) just like MSR has said, but I personally feel that the adaptor cap should be included in the weigh-in. Including the adaptor cap bumps the weight up to 8.7 oz (247 g). I feel this "modified" weight is important to note because the adaptor cap needs to be used to mate the output end of the pump to a Nalgene bottle or MSR bladder (or any other compatible wide-mouth hydration system). In fact, from the directions for backflushing, the adaptor cap is apparently essential.

The included stuff sack is very handy. With a little bit of thought I was able to figure out the right system for packing the filter and included accessories away into it for easy access. Another nice thing about the stuff sack is the instructional tag sewn into the inside of the bag which has diagrams on each side showing me how to assemble and disassemble the filter for backflushing. I can be sort of forgetful, and early on in the testing it will be nice to have a safeguard in place in case I can't remember which way to insert the check valves (more on that below).

HyperFlow Packed

One thing that dumbstruck me is the number of instruction manuals included with the HyperFlow. Total there were nine sets of instructions in various languages only some of which I was even able to identify (I'm pretty sure about the English one, Spanish, German, French, Russian and I think Chinese...). After getting over the language shock I poked around in the English one and found it very helpful in figuring out some of the backflushing and cleaning operations that I'll need to do. I do have to say though that probably the best instructions I found were actually on the MSR website, in particular a few videos they had posted that demonstrate several things, including a step by step demonstration on how to backflush the HyperFlow.

I am very pleased with the out-of-the-box quality of the HyperFlow. It is free of any obvious manufacturing defects and does not feel even the slightest bit flimsy in my hands.

Care & Maintenance

From reading the instructions I believe that the routine maintenance that I will be performing most often is backflushing. The backflushing process initially appeared to be pretty daunting and I wasn't looking forward to it. Then I found the instructional video on MSR's website and my opinion completely changed. MSR recommends that the HyperFlow be backflushed after about every 8L of water pumped. I'm not an expert by any means, but it seems to me that backflushing is basically just reversing the flow of the pump to blow out any sediment or other debris that starts to gunk up the "intake" end of the filter media. The process really isn't too complicated, and with a few practices and the help of the handy dandy YouTube video, I'm able to do complete the entire process in only a few minutes. Of course, at this point I've yet to try it in the field… so who knows what challenges that might bring. I mentioned before an instructional video posted on the HyperFlow page of the MSR website. This video is by far the most helpful thing I viewed or read on how to backflush the filter. Even in my utterly confused state from all the diagrams and text instructions it taught me how to do it in under two minutes.

There are a few other care items covered in the instructions that I found useful. There are instructions to disinfect the filter by flushing a very mild bleach and water solution through it before storage, instructions to clean the check valves and the pre-filter, and lubricating the O-ring on the piston inside the pump cylinder.

There are also a few warnings in the literature provided with the HyperFlow. It is made very clear that great care needs to be taken to avoid freezing the HyperFlow. According to MSR, if the filter is frozen it can crack and damage the filter media which could compromise the filtration process of the water. The instructions also warn to carefully avoid dropping, falls, or impact with solid objects because this could also cause damage to the filter media. I guess all of this makes perfect sense, but it does make me a little bit paranoid about taking care of the HyperFlow.

Down the Trail

I think the HyperFlow is a product with mountains of potential. It is compact, lightweight, easy to use, and my first impression is that it is a well built product. I am also extremely pleased at the abundance of information available on the filter's use, care, and troubleshooting. I can't wait for next weekend when I'll be hitting the trail with the HyperFlow for the first time!


Field Locations and Conditions

The MSR HyperFlow has been called into service on the trails on and around Lake Okeechobee, the spur trails of the Florida Trail, and in Myakka River State Park. Temperatures have ranged between 46 and 92 F (8 and 33 C) over the course of the field testing period with precipitation on one occasion.

As for water sources, I have pumped directly from the tributaries that feed the creeks running into Lake Okeechobee, I have pumped from a water bag with water gathered from those tributaries, and I have pumped from a water bag filled by well pumps in Myakka.

Field Observations

Ready for filtration action!

One of the best things has to be the packed size and low weight. I've seen hikers out there with some real clunkers but the HyperFlow certainly isn't one of them. I've found that I can easily justify carrying the filter in my daypack so I can reduce the water I have to lug, but the bulk and weight savings also mean that I can pack it pretty much anywhere in my bigger packs as well. I used to not be able to carry my filter in the lid of my pack because it got annoying when it moved around too much, but I haven't been noticing the HyperFlow at all really. This means that I can stash the HyperFlow where it is more easily accessible, which is convenient for me.

It isn't just the packed size and weight that I like though. The HyperFlow is very comfortable to hold and pump with. The action on the pump is smooth and steady, and it does not require an absurd amount of force to operate. I haven't ever found myself getting physically tired or fatigued while pumping which is very nice because I get awful cranky when that happens. The pumping motion feels very familiar and natural, unlike several other pumps I have used.

HyperFlow to NalgeneHyperFlow to Hydration BladderI also really like how easy it is to fill all my different hydration systems. The image to the left is of the HyperFlow hooked up to a Nalgene bottle with the connection cap. One of the things I liked the most about my old MSR MiniWorks is how my Nalgenes screwed right into the base so there was no holding a bottle between my knees while trying to squirt water into the opening with an outlet tube which made the whole process look like some awkward dance. I remain very pleased and dance-free since the HyperFlow offers the same convenience. One of the things that I've done with the HyperFlow that I never did with my other filters, however, is fill my hydration bladder without ever having to take it out of my backpack. Sure the HyperFlow isn't the only filter that does this, but it is a new experience for me just the same. I love not having to wrestle my reservoir out of my pack, fill it, and then wrestle it back in all while the bag is half packed. The long inlet tube between the prefilter and the filter pump, plus the tubing from the hydration bladder to the outlet port on the filter pump, allow me to pump easily from my hanging water bags while keeping the pack on the ground which once again avoids the crazy dance.

As for the actual performance of the filter, I have been very impressed. Compared to other filters I have used, this sucker really cranks out the clean water much quicker. To date I would estimate that I have pumped approximately 15L of water in the field. I have back flushed the HyperFlow twice while in the field, but this was for testing purposes both times not for performance issues. I have also back flushed the filter each time I returned home after treks as part of my routine maintenance. With just the basic back flushing recommended by MSR, I haven't noticed any real slowdown on the output of the filter.

One thing that is important to note, as one may gather from the photo at the beginning of my Field Report, is that on all but one occasion I pumped the unfiltered water from my water bag as opposed to directly from the water source. Generally speaking, I always pump from a bag primarily because in my opinion and experience I generally get better longevity out of my filters before they need cleaned or maintained by allowing the sediment and silt in the water to settle to the bottom of the bag. This saves a lot of strain on the prefilter and filter element, so I've stuck with it.

The only real performance issue I've had to date is with the prefilter. The difficulty I've been having is in keeping the intake/filter side pointed down both in my water bag and when pumping directly from a source. For whatever reason, the prefilter is constantly flipping itself intake side up. Sometimes this will cause the filter to take in a gulp of air. While this doesn't damage the filter and doesn't appear to have any ill effects on anything, it does slow the pumping process down. I'm working on a few ideas for a solution, which I should have available in my Long Term Report.


Down the Trail

This thing is great and I'm really loving it so far. The lightweight and compact design makes it very easy to pack, it is comfortable and easy to use, pumps a whole lot of water very quickly, and is easy to care for and troubleshoot. I don't know what more I could ask out of my filter. If only I could figure out how to keep the prefilter face down in the water...

The next few months will bring me to a couple of locations unlike my usual destinations which should offer some great new testing opportunities, so please check back in late July for the final installment of my report.


Testing Conditions and Locations

The final two months of my testing brought me up into Massachusetts and Maine which provided me a bit of relief from the oppressive Florida heat. The HyperFlow filtered my and my group's water on trips to Folly Pond in Maine, a dayhike in Southern Maine, and a short overnighter in Florida.

Elevations have ranged between sea level and 285 ft (0 m - 87 m), temperatures in Maine ranged from 52 F during the night up to around 75 F during the day (11 C - 24 C) with temperatures in Florida starting at 75 F and rose to nearly 95 F (24 C - 35 C), and I encountered precipitation on two of the occasions.

As with my Field Report, I pumped water both directly from the source and from a water bag during each trip.

Long Term Observations

The MSR HyperFlow has continued to perform very well over the last few months of my testing. My findings since my Field Report have been consistent with what I have already reported. There are, however, a few things that I'd like to expand on.

One thing I've gotten a real opportunity to observe over the last two months is how simple the HyperFlow is to use even for people who don't have any experience with it. On my recent trips I made it a point to observe novices and other people who had never used the HyperFlow. What I noticed was that the HyperFlow was something that could be easily figured out by almost anyone. Everyone in my group was able to pick it right up and figure out how to use it relatively easily. I believe this is a testament to the usability of a product, and I was impressed by it. The last thing I want to have to do is sit everyone down and teach them how to do something when I'm tired at camp and just want to relax, so I appreciated the short learning curve.

During my long term testing I would estimate that I have pumped approximately 30 more liters of water through the filter. Since it has just been oppressively hot here in Florida and I have been traveling with larger parties on my recent trips I have put quite an additional load on it. On one of my trips where I estimate I pumped about 20L (5.28 gal) of water I backflushed the filter after about 15L (3.96 gal) when the output appeared to slow a bit. I contribute the slowdown to the fact I was pumping directly from a water source most of the time and when I did pump from the bag, because we were pumping so much, the water did not have a very good chance to settle. Even so, 15L before backflushing is nearly double MSR's estimate of needing to backflush about every 8L.

I much prefer the backflushing system to improve flow rate than the field maintenance I've had to perform on other filters. I've really only used ceramic/charcoal element filters in the past and cleaning those in the field was a real pain in the backside... if not impossible. From a field maintenance standpoint the HyperFlow is much easier for me.

Long term durability has also been very good. The filter element appears to be in great shape upon visual inspection. The inlet tubing is still in good condition. There are no cracks or other damages to the red plastic housing or the black "rubberized" grip portions of the pump. It pretty much looks brand new.

The only thing that I'm continuing to struggle with is the pre-filter. The darn thing just wants to flip intake-side-up in the water and I haven't really been able to figure out a consistent way of keeping it face down. I've used the hook and loop straps on the pre-filter to attach it to my trekking pole which I've stuck out into the water and this did the job... but it was a real pain and is pretty impractical for me considering I use both my trekking poles to setup my Tarptent in camp. I'd like to see MSR address this pre-filter issue going forward.

The Last Word

I think it's pretty obvious from my entire test report here that I really, really, really like this filter. The compact size, low weight, compatibility with all of my hydration systems, high flow rate, and ease of care and use are all major factors that have lead to my satisfaction. The only thing that ever disappointed me about it was the trouble I've had throughout the test with the pre-filter flipping up. At this point, my old filter has been retired. The MSR HyperFlow will be taking care of my water for the foreseeable future.

This concludes my Test Series on the MSR HyperFlow. I would like to thank MSR and for the opportunity to test such an excellent product. Happy trails!

This report was created with the Report Writer Version 1.5 Copyright 2009. All rights reserved.

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