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Gear Workshop The Gear Workshop forum is for the discussion of homemade backpacking gear, gear modifications, and repairs.


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  #1  
Old 05-18-2007, 04:41 PM
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Reality Reality is offline
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Lightweight Water Treatment Option: MSR Sweetwater (Modified)

Lightweight Water Treatment Options: MSR Sweetwater (Modified)

Series Notes: This post is the first in a series of water treatment options (8 ounces or less) that I'll be sharing as time goes on. I have several other options that I've tested and intend to write about in the near future. There are certainly more options than what I'll share in this series - but I've selected a few that I feel will be of particular interest.

Each option in the series can be used for total water purification - removal of all common pathogens including viruses - when used in conjunction with a halogen/chemical or other lightweight purification method (which will be fully explained for each option shared in this series).



MSR Sweetwater (Before Modifications)


MSR Sweetwater (Modified)


The MSR Sweetwater is an excellent water filter without any modifications. I plan to share more regarding this filter's performance (separately) at a later date.

MSR lists this microfilter's weight at 11 ounces. However, without the cleaning brush and stuff sack, mine weighed in at 10.2 ounces out of the box (on a calibrated scale).

It features a replaceable 0.2-micron labyrinth depth filter and granular activated carbon. The MSR Sweetwater removes 99.9999% of waterborne bacteria and 99.9% of parasites such as Giardia and Cryptosporidium. This filter (by definition) does not remove viruses; therefore, water can be pre or post treated with a chemical such as chlorine dioxide or Sweetwater Purifier Solution for virus removal.


Modifications


Disclaimer: The following modifications are not necessarily recommended or endorsed by Mountain Safety Research (MSR), and the reader should be aware that any modifications to the MSR Sweetwater filter may void the manufacturer's warranty of the product.


Hoses (1.45 ounce reduction)


The Sweetwater comes with two (32" ea.) silicone hoses: one for water intake (black) and the other for water output (clear).

I've completely removed the output hose (1.05 oz) and replaced it with a quick release fitting on a 2" section of silicone hose (0.15 oz).

Because the output hose (clear) has been removed (reduced), the filter (output) needs to be closer to your water container than it would have been using the entire hose. Or, in this case, a quick release adapter (male) can be added with a short section of tubing (as indicated above), so that it can utilize an already carried hydration bladder hose (fitted with a female quick release at hose input). This allows direct pumping (filtering) into the hydration reservoir.


Output Modification

I've removed 10 inches of the intake (black) hose for a 0.40 ounce reduction.

By shortening the intake hose, it requires that one be a mere 10 inches closer to the water source. It's worth noting that most survival experts recommend carrying a 12 inch piece of tubing for water seeps. So, while it may not be comfortable in all situations to use a modified 22 inch filter intake hose, it's certainly not putting you at any significant disadvantage (in most common situations).


Float (0.0 oz)


I've completely removed the float, since I have little, if any, need for it. However, this did not make any significant change in weight. If your usage can be enhanced by use of the float, keep it. It weighs less than a gram.


Housing (0.25 ounce reduction / 1.25" length reduction)


On the intake end of the filter housing there is a section (roughly 1 1/4/ inches) that extends down below the intake fitting. My understanding of this extension is that it allows the filter to be positioned in an upright position when it's not in use (hose removed) -- it may also provide some protection to the intake fitting, though this protection is not provided for the seemingly more vulnerable output fitting.

I used my handy rotary tool to completely remove this extension (see disclaimer above). It serves no functional purpose in water treatment, and its removal netted both weight (0.25 oz) and size (approx. 1.25") reductions.


Housing Reduction


Prefilter (potential 0.5 ounce reduction)

The weighted 80-micron prefilter may be replaced with something lighter such as a durable micro-porous fabric. Unless you have a better option, it's best to use the original prefilter. It's weighted to help keep the intake hose in the water source. There are other methods that can be used to accomplish this, but the original is a beneficial half-ounce option.



Original Prefilter


If all of the above modifications are made, the MSR Sweetwater is reduced to an 8-ounce filter. Further modifications (as follows) can be made to lower the filter's weight well below 7 ounces.


Lever/Handle (approx. 1.5 ounces)


I did some experimenting with pumping water without the use of the level. I simply disconnected the lever, then pulled and pushed the pump piston by using my thump and index finger. There are other ways to grip the lever connector - perhaps even with the use of a stick in the field. Using my fingers, I was able to easily pump 2 liters of water into a hydration bladder in just under 2 minutes. It was not as comfortable or efficient as using the lever, but it was certainly doable. Worth considering!

Before removing the lever, it's recommended that you first disconnect it (as you would for storage) and pump using the aforementioned method. If you're comfortable with the action, you can remove it for a significant weight savings (overall).



Pumping Sans Lever (Handle)


[Note: It may be more difficult to pump without the lever in cold weather - though most do not use filters in the winter (depending upon circumstances).]


Water Purification

Because the MSR Sweetwater does not remove viruses, it's recommended that something additional be used with this microfilter for virus elimination. There are several chemical products that will do the job with minimal additional weight: Katadyn Micropur Tablets, Potable Aqua Chlorine Dioxide Tablets, Aqua Mira Water Purifier Tablets), or MSR Sweetwater Purifier Solution.

Micropur tablets, for example, weigh just over half an ounce for 30 individually sealed tablets - enough to treat 30 liters of water. A fraction of that can be carried for most (solo) weekend trips.

Chemical treatment can be added prior to filtering with the MSR Sweetwater or after. If you're sensitive to the taste of chlorine compounds, you may wish to add the chemical prior to filtering (after the prescribed treatment time).

These tablets, when used as directed, can eliminate all common pathogens (bacteria, viruses, and protozoan cysts). However, they do nothing to remove particulate-matter or unpleasant tastes, odors, and discoloration.

[As an alternative, beyond the scope of this 8-ounce or less option, an inline purifier or a UV device can be used in lieu of chemical treatment. They can be used without filtration as well, but without the carbon-microfiltration benefits thereof. Options are available weighing mere ounces.]


Carbon

A pleasing attribute that the MSR Sweetwater offers over purification tablets/devices, is it's layer of activated carbon. If you're like most people, you don't necessarily enjoy drinking green, yellow, or muddy water. Heavy rains, poor water sources, and unexpected contamination can all affect the taste, odor, appearance, and overall quality of backcountry drinking water. Carbon does a good job of removing much of the unpleasant adulterants, and it also removes the aftertaste from chemical treatment. Keeping oneself well-hydrated may be more likely (pleasant) if the water is refreshingly clean.

By the way, using your chemical treatment before filtering also helps protect from bacteria growth in the carbon layer.

[Note: A solid carbon block (as in the MSR Miniworks) is preferred over granular carbon, both for its efficiency and bacterial control. However, this is not necessary if other precautions (indicated above) are taken.]


Miscellaneous Comments


A microfilter is not recommended for use in cold (freezing) weather, since the residual water in the filter is likely to freeze (unless specifically protected).

The weight of the MSR Sweetwater will increase after use, due to water that remains in the filter after pumping. It's recommend that you be sure to pump out as much water as possible, once the intake hose is removed from the source. In my testing, the weight increased as much as 1.5 ounces after use. Though I've been able to pump and/or shake most of this out.


Conclusion


The modified MSR Sweetwater makes a compact, lightweight backcountry water treatment device. For some, this 7 or 8 ounce option (depending upon extent of modifications) may be worth considering for use on their backpacking trips. It offers complete pathogen-stopping water treatment (with chemicals) and greatly enhances the drinking experience by removing unpleasant tastes and odors.



MSR Sweetwater (Modified)


Note: It is understood that this water treatment option is not for everyone. There are a variety of factors that may or may not make this a good choice such as (but not limited to) time of year, water source issues, and physical conditions (e.g. personal strength). This is merely an option to consider. It's understood that there may be good reason why an individual may not choose this particular method, but the same is true of any other. Moreover, I'm sharing these options for educational purposes. And I am not necessarily endorsing any one particular method in this series.
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  #2  
Old 05-18-2007, 05:48 PM
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roverboy roverboy is offline
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Reality,
Great post & pics! I've been on & off the fence about using a filter. The only downside to carrying one for me is the weight. I don't mind pumping & I like the idea of REMOVING nasties, not just killing them.

The carbon does help with the overall taste & smell. I ran down to the local beaver pond the other day to try filtered water using my Katadyn hiker Pro & Micropur vs. using a small bottle cap/screen & Micropur. The water was much clearer (still somewhat of a brownish tint), had less odor & tasted better with the filter.

I'm a believer in the Micropur tabs as well after reading some of your comments in other posts. It's lightweight easy to use insurance against viruses (just in case).

This is a true 7-8 oz compact solution for a complete water treatment system. Looking forward to what else you have coming.
Thanks!
Barnett
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  #3  
Old 05-18-2007, 05:53 PM
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Reality Reality is offline
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Quote:
Originally Posted by Barnett_Childress
This is a true 7-8 oz compact solution for a complete water treatment system. Looking forward to what else you have coming.

Thanks for your comments on the modified Sweetwater.

By the way, I like the fact that you conduct your own testing to find a method that suits your needs and desires.

Reality
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Old 05-18-2007, 09:29 PM
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Perkolady Perkolady is offline
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Excellent beginning to a water treatment option series, Reality !

Though I don't always carry my Sweetwater filter, there are certainly times when it is certainly necessary.

Total water purification is a topic that can always use clarifying. Thanks for the informative post!

Thanks as well for the great weight saving ideas! I will be giving some of them a try

Could you please explain a little more about your quick release fitting?

Thanks!
Perkolady

Last edited by Perkolady : 05-18-2007 at 09:37 PM.
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  #5  
Old 05-19-2007, 03:54 AM
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Quoddy Quoddy is offline
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"Value" of Filter

Excellent item coverage and modification. I recently purchased a Katadyn Hiker Pro and added the MSR Sweetwater Pre-Filter. My only concern is the weight, since the "value" of this type of pump to me is about 8 oz. Now you've got me looking at ways to cut back on a couple of ounces to get it near that value. I'm still planning on using AquaMira in many situations.

Value= weight I'm willing to carry to reap the benefit of the item.
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  #6  
Old 05-19-2007, 10:56 AM
© 2006-2016 Practical Backpacking™ / All Rights Reserved
Reality Reality is offline
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Quote:
Originally Posted by Perkolady
Thanks for the informative post!

You're welcome. I'm glad it was of interest to you...

Quote:
Originally Posted by Perkolady
Could you please explain a little more about your quick release fitting?



I used a quick release fitting (shown above) - which is a Katadyn Quick Fill Hydration Pack Adapter. It's used to connect a water filter output to a hydration bladder's drinking tube. This allows direct filling from the pump (microfilter) to the bladder without removing the bladder from the backpack (if desired). However, this setup (MSR Sweetwater Modified) does not necessitate connecting the filter to a hydration pack - simply pump water into whatever container you desire (even without the fitting).

For those who are interested in connecting their filter's output to their drinking tube, a female quick connect fitting is needed on the end of the drinking tube. Nalgene makes an excellent product (shown below) that provides the female fitting that's needed on the drinking tube and a special bite valve that easily disconnects and reconnects as desired.



Nalgene Quick Connect Articulated Bite Valve Conversion Kit


So, what you have in the end is the Katadyn fitting installed on the filter's output tube and the Nalgene kit connected on the hydration tube (allowing either the bite valve or the filter output to be easily quick-connected as needed).





Reality
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  #7  
Old 05-19-2007, 11:39 AM
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Perkolady Perkolady is offline
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Well, this certainly would reduce the amount of dread associated with filling the hydration bladder!

Thank you once again, Reality !!

Perkolady
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  #8  
Old 05-19-2007, 12:06 PM
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Reality Reality is offline
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Quote:
Originally Posted by Quoddy
Excellent item coverage and modification.

Thank you.

Quote:
Originally Posted by Quoddy
My only concern is the weight, since the "value" of this type of pump to me is about 8 oz. Now you've got me looking at ways to cut back on a couple of ounces to get it near that value. [...]

Value= weight I'm willing to carry to reap the benefit of the item.

I agree with your thoughts on this.

I'm much more impressed with the practice of carrying what one wants (at a smart weight), than I am with just doing without what's wanted simply based upon weight. Weight is certainly a factor, but in my book its only one factor.

We all should determine what works best for us as individuals (based upon our diverse needs/desires), and not (in my opinion) make it all about numbers.

Thanks for sharing.

Reality
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  #9  
Old 05-19-2007, 02:40 PM
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big_load big_load is offline
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This is an interesting project. The Sweetwater was the first filter I used. What I liked most about it was the light weight, how well the prefilter kept the intake at the desired depth, and relative ease of pumping. What I disliked was how quickly the filter clogged and how it sprayed as clogging ensued. I always felt the need to carry a spare cartridge.


Have you used this setup long enough to clog a filter yet? I'm especially curious about how well the modified lever works when cleaning time approaches.
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  #10  
Old 05-19-2007, 03:54 PM
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Reality Reality is offline
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Quote:
Originally Posted by big_load
Have you used this setup long enough to clog a filter yet? I'm especially curious about how well the modified lever works when cleaning time approaches.

My intention was to provide an 8-ounce or less, modified MSR Sweetwater water treatment option. It should perform just as good as it does minus the modifications. The mods didn't upgrade the efficiency in any way. How effective this option is remains in the functionality of the microfilter's design and (to a certain extent) the expertise of the user.

There are steps to take with microfilters to inhibit clogging. As with most things, there are pros and cons with regard to using a filter in the backcountry.

My goal was to move the weight from the con column into the pro column. It's not perfect - merely an option for those who find it practical.

I'll keep you posted on any further developments on this.

Reality
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