View Full Version : MSR HyperFlow - Back-flush with Citric Acid Solution - Wow!
Hello all!
I really love my little MSR HyperFlow filter - it has many benefits. Many people have complained about how fast it clogs up and how the back-flushing procedure does not fully restore flow. I have also experienced this problem, especially after filtering pond or lake water (or stream water high in tree tannins).
In order to help dissolve the gunk that builds up in the ceramic tubes that make up the filter, I tried mixing two tablespoons of citric acid (also know as "lemon salt") or "acid blend" (used in winemaking) into the filtered water I use for back-flushing.
Wow - what a difference! With just one back-flush the filter is restored to normal operation. It really works well if use sub-boiling hot water.
Has anyone else tried a procedure like this? I was planning on sharing it with MSR to get their thoughts. I do not believe that the citric acid blend will do anything to hurt the filter.
Thoughts?
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Starchild
05-11-2015, 08:17
I do not believe that the citric acid blend will do anything to hurt the filter.
Thoughts?
My thoughts are exactly did you damage the filter in doing this.
And it's not just chemicals you are using but also elevated temperatures so a combination of things that may react differently when used together then just using them on their own.
One thing you can try out is leave that stuff in the filter longer and see of it improves the flow further, if so, especially if it improves beyond original flow rates you most likely destroyed it. If not however you still may have destroyed it, or you may just have cleaned it, it would be a unknown at that point.
You can contact MSR, I would think their reply would be that they can not recommend that method of cleaning and suggest you don't use that filter for water purification, etc. but maybe they can be helped or give you helpful info IDK.
If you are determined to use this cleaned filter you might try buying a new one, get the flow rate using clean water that should not clog it, then treat it, then get the flow rate after treatment, if it increases then I would not trust that method of cleaning, but if it was the same then you now have 2 filters you are willing to use.
Thanks for that reply!
Maybe I should clarify that citric acid is a food, safe for human consumption. It is commonly found in fruit such as lemons and oranges.
What I did would be the equivalent of running lemonade or orange juice through the filter - I do not think it did any damage.
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Starchild
05-12-2015, 06:17
Thanks for that reply!
Maybe I should clarify that citric acid is a food, safe for human consumption. It is commonly found in fruit such as lemons and oranges.
What I did would be the equivalent of running lemonade or orange juice through the filter - I do not think it did any damage.
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You also said you ran it though near boiling, is the filter designed for that type of backflushing?
IIRC another filter (Sawyer) uses a rubber like resin or adhesive to seal the filter so water can only pass though the membrane. High temperatures may not be recommended I don't know if it would weaken the seal.
I started with water that was less than 100 C, poured it into a bottle, mixed in the citric acid powder and then back flushed the filter. The water temperature was such that you could touch it without being scalded - I again doubt and damage was done.
This filter does have an issue with clogging quickly in the field. During extended trips this can become a problem. It's a great product - I'm looking for a solution - I will consult our MSR rep and post the results here.
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If the filter is made up of ceramic tubes as someone above said then acid would eat at the ceramic. It would damage the ceramic in the long run. The reason you might get better flow is that the acid is taking off some of the surface ceramic and the gunk with it. If that is the case the tubes would allow larger microns through than the filter advertises.
Again - this is citric acid you buy in a supermarket that you use in cooking and you eat. It is used as a wash - and flushed out after a few seconds. It is not HCL.
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And the filter cartridge is a consumable item that is replaced with new every season.
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Turtle-2013
05-13-2015, 07:45
Magneto ... I'm really interested in what MSR says ... I suspect your acid solution isn't much or any more "off ph" than some of the water sources that I have used over the years. So, I'd be surprised if you did damage, however since one would hope that they know their product best, I'd love to know if they give you an opinion. It would be a great lab project for a college student, to determine actual "real-world" micron filtration before and after the acid wash!!!
Thanks! I sent them an email yesterday. It might also be the case that just using hot water really helps too. I haven't had a chance to try it in the field yet.
I'm heading back out for 4 weeks in mid June - i haven't decided yet if I am going to carry a stove. I did an 11 day stretch in the HMW last summer where I used the HyperFlow. Nothing is faster - also it's great for sucking water out of low-flowing springs and where you have to reach down under rocks. I really like it. I've used water treatment tabs, but the lack of filtration results in all sorts of odd flavors.
During my hike the filter did slow down and become hard to pump, but never to the point where I couldn't do it. When I got home, I tried the warm water / citric acid back flush. As I said, the results were fantastic after just one treatment.
So I did some research and citric acid can be used to etch ceramics, but the concentrations were much higher (2%) and the exposure Rines were much longer (more than 8 hours). I don't know the exact composition of the 100s of tiny tubes that make up the filter cartridge (you can see the ends under a microscope), but I don't think a few minutes at a low concentration will do damage.
I will post MSR's response.
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Starchild
05-13-2015, 10:16
So I did some research and citric acid can be used to etch ceramics, but the concentrations were much higher (2%) and the exposure Rines were much longer (more than 8 hours). ...
While this is true, my concern is when you use citric acid to etch ceramanics, you only apply the the solution to the outside - which I assume it has to slowly eat it's way in but in this case you, even with the much lower concentration and times, you are exposing the insides of the filter, the solution is permeating the entire thing through and through. The passages of a absolute size are now all being exposed to a etching solution all at once, so it may not take much time or concentration this way.
Not saying this is the case, however from what you relayed for me the filter's status would be unknown and unless MSR can get back to you with a answer, or you have the ability to lab test it, the only way to truly know the status would be to get very sick (as not getting sick can not prove it is working).
I will post MSR's response.
Really curious about this myself.
Gray Bear
05-13-2015, 10:36
I also own this filter. I've heard the horror stories about the filters and hesitated to pick one up. I've never had any serious issues with my filter but I stay right on top of maintenance. If I'm forced to filter nasty stuff and see performance starting to slip as soon as I find decent water I back flush a couple of liters. Its not too tough to do if you take the time to practice at home. Once I'm home I'm pretty anal about getting my gear out of my pack to air out and a filter douche is always a priority. It will be interesting to hear what MSR says but personally I've never had a problem with the SOP. A second filter is always an option if you don't want to back flush in the field.
Still waiting on MSR.
I don't see a need for lab tests here. The filter is still working just fine. I'm not at all worried about it.
Next time I back flush it, I'm going to try just hot water. I suspect the heat is a big part of dissolving the organics that build up in the tube openings.
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Starchild
05-13-2015, 11:24
There is a test for this filter to test the integrity of the membrane:
https://www.youtube.com/watch?v=cp6LTxHuXao
Can't wait for the results.
Gray Bear
05-13-2015, 11:36
Still waiting on MSR.
I don't see a need for lab tests here. The filter is still working just fine. I'm not at all worried about it.
Next time I back flush it, I'm going to try just hot water. I suspect the heat is a big part of dissolving the organics that build up in the tube openings.
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I doubt you'll have any issues with your method. Its not like you're soaking it right? are you flushing with fresh water after you use your super secret sauce?
Walkintom
05-13-2015, 12:50
One of the things I was told long long ago when I worked for a guy who built pressure washers was: never, ever, run acid through the pump. It will etch the plungers (ceramic) and then they'll leak, break, or both and you'll be rebuilding the pump in short order.
That acid was admittedly much more concentrated than what you're using, but the porous nature of a ceramic filter would concern me a lot with an acidic liquid being used to clean it.
I'll be interested to hear if MSR says they think it's ok as well as whether it passes the test SC linked to.
The Splitter
05-13-2015, 15:30
Embarrassingly I'll admit I didn't even know I was supposed to back flush the filter. I thought I was just supposed to replace the filter every thousand liters. I've probably filtered around a hundred or a little less liters since I bought it and thought I was imagining things as to why it was getting so hard to pump.
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ive had a hyperflow since they first came out...
here's my thoughts-----great filter for a solo backpacker like myself.......nice and light and easy to use....
except for the backflushing experience...
ive tried a few times and ive only successfully gotten it to backflush correctly once......most times when i try a backflush----it creates a vacuum and seizes up..........MSR had no response other than to keep trying when i asked about it...
so, what i did----was buy replacement filters in bulk for very cheap (8 bucks a pop)........i then change it in spring and use it throughout the year for my various trips.........and yes, a few months in---i have to put more muscle into the action......but it still does the job....
now on to the experiment at hand--
In order to help dissolve the gunk that builds up in the ceramic tubes that make up the filter,
well.....first off----the filter is not ceramic......they are the hollow fiber tubes.........which is essentially plastic.........not ceramic...
me thinks with adding boiling or close to boiling water, it will expand the tubes allowing more things to pass through.......
and yes, you could still use it, but the risk of getting something from the water will increase...
but, obviously interested in what MSR says about this.....
Water does not pass through the hollow fiber tubes - in one end and out the other - like a tunnel. The tubes are installed in a "U" shape and water is pumped into the tube from both ends simultaneously and then forced through the through the material. The contaminates stay in the tube which eventually causes the filter to slow down and become hard to pump. Back flushing forces water back through the material into the tube and then out the way it originally came in. Both ends of the each tube are located at the dirty water inlet. It is the pourus nature of the material the tubes are made of - not the diameter of the tubes - that allows the filter to function.
I've examined the cartridge under a microscope and can see no difference in the tube size or the appearance of the material after back-flushing as I described. You can clearly see both ends of the tubes at the inlet end and by looking at the other end of the cartridge, you can see the bend of end of the "U"s.
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Turtle-2013
05-14-2015, 07:25
Thank you TNHiker and Magneto for clearing up the ceramic issue ... while I was certain they weren't ceramic, I hadn't taken the time to actually look it up to confirm. Still waiting for the opinion from MSR. MY solution to the backwash issue was to construct a small adapter that could be put on a utility sink faucet or outdoor faucet and then running water through it backwards at increasing pressure until it is running well. This has returned the filter to near (but not completely) new function....
Starchild
05-14-2015, 07:51
Water does not pass through the hollow fiber tubes - in one end and out the other - like a tunnel. The tubes are installed in a "U" shape and water is pumped into the tube from both ends simultaneously and then forced through the through the material. The contaminates stay in the tube which eventually causes the filter to slow down and become hard to pump. Back flushing forces water back through the material into the tube and then out the way it originally came in. Both ends of the each tube are located at the dirty water inlet. It is the pourus nature of the material the tubes are made of - not the diameter of the tubes - that allows the filter to function.
I've examined the cartridge under a microscope and can see no difference in the tube size or the appearance of the material after back-flushing as I described. You can clearly see both ends of the tubes at the inlet end and by looking at the other end of the cartridge, you can see the bend of end of the "U"s.
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I sort of new how it worked, though I assumed similar to the squeeze which you now confirmed. What I was getting at is not the tubes themselves were damaged, but the very fine/small passageways that the water must take to get from inside the tube to outside the tube. I don't know if it would be possible to see them or damage to them with a optical microscope, they may be too small. If your filter filters out virus, they would be too small for a optical microscope. If bacteria only you should be able to see them, or at least the surface openings.
Also it would be nice to see that material under a microscope, any way you could post a pict?
Did you have a chance to run that very simple test I linked to?
I'll try - I have a camera attachment I use for photographing electronic circuit boards. I seriously doubt anything has been damaged. My guess is warm water is much more effective at back-flushing than ice-cold. This is true with most things - warm is more effective than cold. I will have to try some further experimentation. Still waiting on MSR.
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Water does not pass through the hollow fiber tubes - in one end and out the other - like a tunnel. The tubes are installed in a "U" shape and water is pumped into the tube from both ends simultaneously and then forced through the through the material.
yeah......that's what i meant----that the water had to pass through the "walls" of the tube in order to be filter........not just go end to end on the tube...
i just think by adding hot water, it would expand the porous (?) material and make larger junk pass through...........
i did notice that the owners manual said to use bleach......not as a backflush but as a mold and bacteria deterrent....
MY solution to the backwash issue was to construct a small adapter that could be put on a utility sink faucet or outdoor faucet and then running water through it backwards at increasing pressure until it is running wel
ha......that exactly what i wanted to do...............basically hook the filter up to a garden hose and run water through it..
but, shopping at the local hardware stores, i couldnt find anything that would fit to the filter..........seemed like it was just a bit small for most adapters...
can you tell me how you did it? i wanna do it that way, as it will make backflushing all that much simpler.......
Still nothing from MSR - I'm not surprised.
I'm going to try just heated water next time. Last time I was out for an extended period, I didn't bring a stove. This time I plan to - so I'll be able to see how well it works. I'll report back later...
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The Splitter
05-15-2015, 09:31
I tried regular back flushing last night and it didn't make any difference, going to try your method tonight.
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Splitter - thanks! Let me know how it goes. In the end, if we end up damaging the filter cartridge (which I doubt), it can be easily replaced. The retail cost is $40.
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im guessing the response from MSR will be something like this----
"thanks for inquiring about our product..........please refer to the owners manual for instructions on how to backflush......thank you"
also, look around on the interwebs and you can usually find the filter for cheaper than 40........
handlebar
05-15-2015, 23:08
I'd suggest calling MSR and ask to talk with the Hyperflow product manager. This person should know how citric acid might affect the filter element.
I can't imagine using hand-hot water would cause damage, and that the heat alone might have given an "improved" backflush. I always use filtered water for backflushing because even tapwater can have small inclusions that would tend to clog the filter.
I'm just back from a trip and need to backflush my filter then filter some water with a bit of bleach before I put it away. I'll do that tomorrow and let you know how hand-hot water alone works.
Thanks to both of you for the replies!
Yes - I think MSR will not modify their recommended procedures in an email to me.
I also think warm water works better than cold and will not harm the filter. I'm going with that.
The cost of the filter is acceptable - I like the product.
I am heading out for an extended period, so field maintenance is important.
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handlebar
05-16-2015, 13:50
I just backflushed plain, hand hot tap water through 3 Hyperflow cartridges. I am very pleased with the results. The flow is nearly that of a brand new filter cartridge and all 3 cartridges passed the integrity test.
I think part of the bad rap the Hyperflow has gotten is due to the old "failure to follow directions"---especially the direction to pump a mild bleach solution through the filter prior to storage and after extended use per MSR directions:
To eliminate the growth of bacteria or mold, always disinfect the filter before or
after long-term storage, or after long-term use (15+ consecutive days).
1. Mix a solution of 2 drops of household bleach to 1 liter of water.
2. Remove Inlet Hose from Inlet Hose Barb.
3. Pump diluted bleach solution through filter.
4. Remove Pump Inlet from container.
Pump filter to purge it of any remaining solution.
Reattach Inlet Hose to Inlet Hose Barb.
5. Air or towel dry all pump assembly parts completely.
NOTE:The inside of the Filter Cartridge will not dry completely, but the
bleach in the solution will prevent the growth of harmful microorganisms.
Sounds about right - hot water is great.
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Turtle-2013
05-16-2015, 19:38
ha......that exactly what i wanted to do...............basically hook the filter up to a garden hose and run water through it..
but, shopping at the local hardware stores, i couldnt find anything that would fit to the filter..........seemed like it was just a bit small for most adapters...
can you tell me how you did it? i wanna do it that way, as it will make backflushing all that much simpler.......
I searched diligently for a screw-on adapter ... since I couldn't find one I settled for the next best ... it is a little clamp-on adapter. I have a female hose adapter on one side and the other fits right on the filter and I tighten the clamp. If you PM me your phone # (text) or email address I will take a pic with my phone and send it to you.
You would probably not want to run unfiltered water through it.
You could back flush with deionized water - you can get it at the supermarket. It is 99.99% pure. As we have been discussing, heated deionized water would be great - but not a solution to use in the field.
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vic_doom69
05-30-2015, 19:21
except for the backflushing experience...
ive tried a few times and ive only successfully gotten it to backflush correctly once......most times when i try a backflush----it creates a vacuum and seizes up..........MSR had no response other than to keep trying when i asked about it...
I started my thru with one of these. Had this problem every time I tried to backflush. Had msr sending me replacement cartridges seemingly at every town stop. Got tired of fooling with it and got some aquamira and never looked back.
I've used mine for 5 years - with proper maintenance it works as advertised. Hot water back flush really helps. MSR also recommends but waiting for a noticeable drop in performance before back flushing - do it every 8 liters. That helps. They also recommend sterilizing with bleach solution after a trip or occasionally during. That helps as the bugs don't get a chance to grow and clog the filter.
The military uses this filter in all sorts of rugged conditions. If you follow the instructions, it works fine.
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