Companion forum thread to:

MSR Hyperflow Microfilter with Modified Cartridge Review

G'Day Rodger
These blokes might think it a little strange that you used your 'thong' under the filter..
Darren

Edited by darren5576 on 05/20/2009 04:07:02 MDT.

Roger,

How much (clean, filtered) water would you estimate would be required to backflush as recommended by MSR?

Thanks

Hi Chris

It's in the article:
"MSR recommends doing a backflush after 8 L, so this was then done. The MSR recommendation, which was followed, is for 10 strokes of backflushing using clean filtered water: about 0.5 L."

Cheers

And I'm sticking with my Sweetwater. Thanks for the great review.

Are other review-collecting sites getting similar responses to the Hyperflow?

Do any other sites have the inclination or capability to apply objective expertise to their testing?

BPL is unique in it's fanaticism, it's devotion, and skill in reviewing products. Other sites may be doing testing and other individuals may be doing "field testing",
but the majority of it is opinion and preference with very little substance.

IMHO.

I had some problems with it being hard to pump after the first couple of days, but learned that if I pumped it slowly it still worked fine. This is also after quite a bit of abuse as I didn't back flush the filter for the first few days.

After 2 or 3 days, we (meaning me) started pumping only water that we needed right away for drinking or a meal and using purification tablets over night for drinking/cooking water for the next day's start. I like this method as the tablets are very light.

So, it's not perfect, has quirks and is a bit expensive, but it's light/small and if you don't try to force the pumping it works great.

Oh, and we were up in the Sierra and all the water was clear and nice, but not perfect as some streams were very shallow.

Note: just to be clear, I was getting really frustrated with this filter when I finally figured out that applying more force created more resistance...I then reduced the force/speed of the pumping and it worked well, but not as fast as the specs say.

Edited by erichodges on 05/20/2009 13:52:24 MDT.

QUESTION to Roger Caffin. I am curious to know the date on the MSR replacement cartridge you received. Presently I have a cartridge with a date of 112808 and I’m experiencing similar issues as you have.

Edited by KENLARSON on 05/20/2009 15:41:58 MDT.

Hi Ken

Old one: '041808' meaning 18-April-2008
New one: '121008' meaning 10-December-2008

Cheers

I suspect that the “error was air” using an outdated backflush procedure BPL followed. The printed instructions included with my filter (4/08 version) have been updated in the video now shown on their site. My 4/08 manual states:

Backflushing the Filter Cartridge
Always perform backflushing in a controlled area to prevent the loss of small parts.
1. Collect ½ liter of filtered water into a clean MSR recommended container.
(See Tips.)
2. Remove Inlet Hose and unscrew Pump Inlet from Pump Cylinder. Do not pump
because trapped air will hamper operation. (See Troubleshooting.)
3. Reverse the Large Check Valve and reinstall it inside Pump Inlet.
4. Pull Pump Cylinder to end of stroke and turn until Piston locks.
Use cylinder to unscrew Piston from Filter Cartridge to reach Small Check
Valve.
5. Reverse the Small Check Valve and reinstall it inside Piston.
6. Thread Pump Cylinder (with Piston and reversed valve) carefully onto the Filter
Cartridge.
NOTE: Both tips of Large and Small Check Valves should point toward
the Pump Inlet
7. Thread Pump Inlet onto the Pump Cylinder. Again, do not pump air into pump.
(See Troubleshooting).
8. Connect container with filtered water to Outlet Adapter (or Outlet Nipple).
If using a hard bottle (Nalgene®), invert container to keep any air from
Outlet Nipple.
If using a flexible water system (MSR® Dromeday™ Bag with Quick Connect™ Bottle
Adapter), purge air from the bag before attaching Outlet Adapter.
If using a personal hydration system (Platypus® Big Zip SL™, CamelBak®), remove
Bite Valve, purge air from bag and Drink Tube, and attach Drink Tube directly onto
Outlet Nipple.
9. Pump 10+ full strokes of filtered water to flush Filter Cartridge.
Wait for Pump Cylinder to fill with water during each stroke.
When backflushing is completed, disassemble pump and reinstall the Large and Small
Check Valves in their original, forward flow position. Dry pump assembly and then
reassemble. CAUTION: Protect Filter Cartridge from accidental drops, which may
damage the filter.


In contrast to these printed instructions, what I have found to work best (note steps 4, 10, & 13) and what the current MSR instructional video now shows is:

”

Secondarily, the most recent review has a picture with the caption, "Pushing on (or downwards) with the testing" and the original review has a picture with the caption, "The pumping action"... they also indicate air introduction to the outer surface of the hollow fibers which may also reduce the filter’s effectiveness.

The following 2007 independent research report entitled, “Unstable filtration behavior with submerged hollow fiber membranes” was authored in part by UNESCO Center for Membrane Science and Technology, Chemical Sciences and Engineering, The University of New South Wales, Sydney, NSW 2052, Australia.

It says in part, “…The formation of these stagnant bubbles is attributed to some ‘dry’ points existing on the internal surface of the hollow fiber membrane. It appears that these ‘dry’ points cause significant and unstable local resistances for the permeate flow inside the fiber lumen. For a fixed average flux the high local resistance results in increased suction pressure in the lumen region downstream of the ‘dry point’ and this shifts an additional flux load to this region. The resultant maldistribution of local fluxes caused by abnormal local flow resistances can markedly affect the filtration behavior of the hollow fiber membrane. Interestingly the effect was not observed for all fibers and appears to require local ‘dry point’ existence within the lumen.

Edited by richard295 on 05/20/2009 21:39:22 MDT.

It's an interesting theory, but having fairly carefully reviewed my notes I don't think so.

I did find that starting the backflushing the first time was slow for the first few strokes, and I am quite willing to accept that air bubbles may have been the problem. Interesting, and thanks for pointing this out. But I tghink they were flushed away after several strokes.

What is revealing is the first filtering cycle, where there was a very noticeable deterioration in ease of pumping as I progressed from bottle 1 to bottle 6. (Bottles are 1.25 L each.) I cannot see that air bubbles could possibly account for this change in resistance while filtering. I was getting an increase in resistance before any backflushing was done.

The second filtering cycle (after the first backflushing) showed the same steady deterioration in ease of pumping as I went from bottle 1 to bottle 6. Again, this is consistent with a steady blocking of the fine pores, not with air bubbles.

I noted:
"Because I knew what to look for, I was able to see a very faint green/brown tinge on the surface of the filter tubes, but it was so faint that a casual user might not see it. It did seem that the same tinge was there before and after the backflushing cycles, meaning that the backflushing process was not able to remove it. This by itself calls into question the effectiveness of the backflushing process for handling typical organic 'stuff' in a water supply."

I do not question the effectiveness of the filter at handling particles at the typical bacteria size. I imagine that if you only ever filtered really clear water the Hyperflow would do a good job. The problem is that the whole design allows typical gloopy organic particles to block up the surface of the tubes, and backflushing does not get them out of the pores.

If MSR put a 15 - 20 micron paper pre-filter before the tubes to handle the gloopy stuff it might make a world of difference - but you would have to change the paper every day.

Beautiful technology, but only for clear water imho.

Cheers

Last fall, in the White Mountains, we used the Hyperflow (pumping water for a family of 4) with pretty similar results. First couple of liters went fine, then it all went steadily downhill. Backflushing helped only minimally. By the end of the 5th day, I was getting pretty exasperated. But backflushing seemed to be different on different days, despite following the same procedure each time. Sometimes it helped more than others.

Returning home, I backflushed MANY, MANY times (lost count) and got it back to almost as good as new. But I'm not sure I'll take it on a trip longer than a weekend.

Contrast this with my Sweetwater, which is not nearly so compact, but always works flawlessly and has a great leverage system so pumping never requires excessive effort.

Roger,

Thank you for your response. I agree "error is air" is only a theory that attempts to account for different people's testing experiences. I also perceive increased pumping resistance proportional to both the water clarity and volume processed. I, like you, agree that "this is consistent with a steady blocking of the fine pores". We differ in the conclusion that as a result of the above the Hyperflow is most appropriate for water without "gloopy organic particles" which plug it up. I concluded that clear water is most easily treated by chemical means; it is only opaque water that requires the weight and the effort of a field-cleanable filter such as the Hyperflow, WaterWorks, Katadyn, etc.

I own two other brands of field cleanable filters: a WaterWorks EX Microfilter and a Katadyn Pocket Filter. I only accept the weight and effort of these mechanical filters when I know I will have to frequently treat opaque water for long periods (for example glacial silt rivers or muddy rivers). All three field cleanable filters exhibit a similar degradation pattern from blocking of the fine pores.

Both the WaterWorks and the Katadyn require that I periodically open up the filter and use a stiff brush to scrape away the outer sheath of the ceramic labyrinth element. With the Waterworks and Katadyn, the cleaning procedure always restores the original pumping efficiency. By contrast, the Hyperflow's original pumping efficiency is not restored unless I follow the modified protocol shown under the column entitled Nisley.

In the field, I use the Hyperflow in both gravity feed mode and manual pump mode. The BA Pumphouse gravity water source is 6L and takes approximately 17 minutes with pristine water and only a few more minutes for farm pond quality water. After a farm pond gravity feed operation, the filter definitely requires backflushing. My experience has been that the backflush operation procedure used is the primary determinate of subsequent manual pump pressure required.

Edited by richard295 on 05/21/2009 10:01:23 MDT.

Hi Richard

More backflushing needed? Maybe. Mind you, the Hiker remains the Gold Standard for filters imho.

However, I have switched to the lighter Steripen Adventurer which treats protozoa, bacteria AND viruses, fast. Having copped it REAL bad from viruses once, and also Giardia twice, I am happier that way.

My personal opinion is that UV can/will replace both chemicals and filters, especially once the UV LEDs get onto the market at a reasonable price.

Cheers

I can report similar issues to the updated review by Roger. Although MSR replaced my original filter with a new one at no cost (kudo to MSR for their effort), on a recent backpack I found that the pump output was severely restricted, would work OK if I went very sloooowly, but in no way gives the result that MSR advertises re: flow/output.

I was sad to see this review. I recently hiked with a friend who has been using this filter for some time in the backcountry with no issues or complaints. She did not have the backflushing issues, reduced flow, or need to change the filters so quickly. She originally had a military version and loved it so much she switched to this one when she couldn't find a civilian source for filter replacement.

I tested this filter on our last hike and it had an amazing rate of flow, the water tasted great, and we dropped the filter element into very shallow, mostly muddy water, with no issues.

I was set to purchase this to replace my current steripen setup, but now I have concerns.

I wonder why she could have so few complaints compared to so many here.

I've posted some of my experiences with the Hyperflow on BPL and another site or two. Following is the history of my Hyperflow. I bought it in 2008 when it first came out on the market, and it worked well for a few days then became almost impossible to pump. MSR acknowledged that there was an issue with the first batch of cartridges (as was documented in the review), and replaced mine at no charge. The new one they sent me went about the same way as the first one where it worked for several days then became really hard to pump. So I sent that one back, and they sent me yet another cartridge. The newest cartridge was first used on the most recent trip I took (part of the AT in Vermont), and it clogged up in about 3 days. My buddy, who also has a Hyperflow and has not previously had issues with his, had his clog up after about 3 days on the same trip. It is notable that we both filtered dirty water from multiple sources, in particular we had to filter out of one of the lakes (Griffith).

The filters are usable if one pumps very slowly, but then its only claim to fame is being a few ounces less than its competitors. I appreciate MSR's customer service, but I've pretty much given up on the filter itself. I think I'm going back to my Katadyn Hiker, my Sweetwater or I may even try the one treatment technology I haven't yet tried...UV.

Edited by Berserker on 06/23/2010 11:24:05 MDT.