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Sawyer Gravity Filter
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Arthur Forbes
(FNF) - F
Sawyer Gravity Filter on 10/25/2010 11:21:39 MDT Print View

I just noticed that Sawyer is now making a clean / dirty bag gravity filter just like the ones from Platty & MSR. I purchased a MSR gravity filter two months ago and this was not on the market then.

There appears to be no advantages over the Platty & MSR version, except the filter does look like it will be much lighter and is not "overbuilt" and armored with rubber the way the Platty & MSR models are.

I have not found just the filter for sale but did find a "gravity filter kit" without the clean/dirty bags which allows you to hook it up to your faucet at home or take it out into the field:

http://www.rei.com/product/801824

The listed weight of this entire setup with hoses & connectors is only 2 oz and I am thinking about replacing the filter that came with my MSR with this one to reduce it's weight - does anyone have any experience with this filter or know how much it weighs on it's own?

It filters down to .1 micron which is better then the all others and it can be backflushed in the field, it's a hollow-fiber filter just like the others. I really like my MSR gravity filter, it was the only one with a built in pre-filter but it's just a bit to heavy and I think this might bring the total weight of my setup down a few ounces and actually give better performance. Any thoughts on this?

Eric Lundquist
(cobberman) - F - M

Locale: Northern Colorado
Re: Sawyer Gravity Filter on 10/25/2010 11:45:47 MDT Print View

Many people on the forums use the Sawyer filter with a platypus as a MYOG gravity system. I have what appears to be the previous generation of the filter (mine is all black) with a slightly different connection system. Sawyer filters are great and can be backflushed at home after the trip or on the trail as well. The only thing you have to worry about is cold temperatures and the filter freezing. Just pack a zip-lock bag and throw it in the bottom of your sleeping bag/quilt if you thing temps will dip that low.

The advantage over the platypus system for me was the weight and that i already owned the necessary clean/dirty containers.

I think my system using some tubing, Sawyer filter, 2L platypus with bottom cutout as 'dirty' container weighs in at 6oz.

Edited by cobberman on 10/25/2010 11:50:03 MDT.

Ike Mouser
(isaac.mouser) - F
Sawyer setup on 10/25/2010 12:14:45 MDT Print View

AT some point i am going to make a system as follows:
(Descending order)
Cuben water scoop bag -> MSR silt stopper -> Sawyer filter -> platy container.

Hopefully i can get rid of the penalty of using the silt stopper via the cuben bag. Allowing me to get alot more life out of my filter by feeding it cleaner water. In the winter, i will hike with the filter element in a jacket pocket. Be careful putting it in a sleeping bag, as it may leak out and your bag will get wet.

Edited by isaac.mouser on 10/25/2010 12:22:19 MDT.

Ike Mouser
(isaac.mouser) - F
ERIC on 10/25/2010 12:48:14 MDT Print View

you are cutting the bottom out of on of the platys and using it as a scoop that way? How do you attach a line to the platypus in order to attach it to a tree for filtering? I normally punch holes in the bottom of the platy(the extra plastic), werap ductape around the line so it doesn't cut into the plastic after repeated use.

Konrad .
(Konrad1013) - MLife
possible on 10/25/2010 13:06:58 MDT Print View

Ike, You can cut out only the bottom of the platy 2l, and still keep the sides where you would punch holes through. The bottom is billowed so that it stands upright. The edges of the bottle go past the bottom as well, so its possible to remove the bottom with precision, and have a functional scoop, yet still have the hard plastic laminated sides to string rope through

Edited by Konrad1013 on 10/25/2010 13:07:41 MDT.

Eric Lundquist
(cobberman) - F - M

Locale: Northern Colorado
Re: possible on 10/25/2010 13:10:56 MDT Print View

This exactly describes my setup. I copied it from my dad because it works so well. I'll post up a photo later to better illustrated what I have going.

Ike Mouser
(isaac.mouser) - F
pic on 10/25/2010 13:12:00 MDT Print View

i was just attaching my line to the billowed sides and reinforcing it. Do you have a pic of yours? sounds better.

Arthur Forbes
(FNF) - F
Cuben water scoop bag on 10/25/2010 15:02:10 MDT Print View

I like your idea, what do you plan to use for the hose connection to the bag, have you found a elbow connection with a flat base that could be glued to a hole cut in the cuben bag?

I could cut up my MSR dirty bag and use its elbow connector with the pre-filter attached......

Ike Mouser
(isaac.mouser) - F
scroll down on 10/25/2010 15:28:53 MDT Print View

http://ultraliteskunkworks.blogspot.com/2005/09/cuben-connection.html

Eric Lundquist
(cobberman) - F - M

Locale: Northern Colorado
Re: Sawyer Gravity Filter on 10/25/2010 19:13:35 MDT Print View

As promised , here are some photos of my Sawyer/Platypus Setup - 6oz

Sawyer Filter_01
Filter package all wrapped up. I use the small cord to hang off of sturdy branches, rocks, or by hand. It works great to wrap back on itself to close the filter package up tight.

Sawyer Filter_02
I carefully cut out the bottom of a 2L Platypus.

Sawyer Filter_03
The full setup.

Sawyer Filter_04
Dirty water bladder.

Sawyer Filter_05
Clean water end, w/ repurposed Camelbak hose.

Sawyer Filter_06
Final weight.

By using the screw lids it prevents the 'clean' water to overfill and loose the rest of the water. I haven't had the need but I imagine I could rig up a shower with this same setup. As opposed to Aqua Mira I don't have to wait to drink the water and the filter takes less than 10 minutes (2L) if you're doing it trailside.

Ike Mouser
(isaac.mouser) - F
revision on 10/26/2010 09:46:08 MDT Print View

i have decided to revise my plan for a filter. i will no longer be using the siltstopper, biodisel micron filter bags are much cheaper. bought in bulk they are something like a dollar a bag. the only thing i am unsure about is what size micron bag i shoukd order:1, .5, 5? if i order too small the flow rate will be affected, too big and i lessen the life of the sawyer.

the bag will be sewn to my cuben collection bag. i believe the bag will allow me to use the sawyer purifier instead of the filter, giving me a totally effective system. i will also not be slowing the gravitational filtering force by sticking a siltstopper in the middle of the process-slowing down the flow.

ken larson has reported good results with this setup: 9 days no change in flow rate or stoppages.

so the final setup will be like:
biodiesel bag-cuben bag-sawyer-hydration drinking platy.

Edited by isaac.mouser on 10/26/2010 09:53:21 MDT.

Greg Mihalik
(greg23) - M

Locale: Colorado
Re: Pre-filters ? on 10/26/2010 12:32:23 MDT Print View

I too was considering a pre-filter- the Siltstopper, at $10 a filter - but the light went back on when I remembered my reason for going with the Saywer in the first place.

You can backflush in the field to restore functionality. So if most water is "pretty good" anyway, why bother with a pre-filter? IF things get slow in the field I can deal with it. At home I'll backflush as part of the cleanup and PM routine.

It comes back to "Don't pack your fears".

Ike Mouser
(isaac.mouser) - F
why prefilter on 10/26/2010 13:10:20 MDT Print View

im not a making a prefilter setup because im afraid of dirty water or device failure, im making it to prolong the lifespan of my mainfilter, thats the purpose of prefilters. before i buy anything i do research for a long time. i"ve been considering updating my filter setup for a year. i was considering the siltstopper.", but micron fuel prefilter bags do the same thing way cheaper and dont slow down flow rate. its about making the right purchase first so you dont have to end up eith a gear closet full of useless gear and an empty wallet. i want to make this setup as easy to use, reliable, long lasting, cost effective, and light(as long as im not sacrificing any of the previously mentioned aspects).

will a prefilter reduce the amount of backflushes required in the life of the filter and make it last longer? without a doubt. for a 1-2oz penalty it seems like a good investment.

btw most of the water i encounter is not good water.

Edited by isaac.mouser on 10/26/2010 13:27:13 MDT.

Eric Lundquist
(cobberman) - F - M

Locale: Northern Colorado
Re: why prefilter on 10/26/2010 13:24:42 MDT Print View

Sawyer claims 1 million gallons over the life of the filter. I don't see the need to prolong it's life in such terms. It's guaranteed to filter 1 million gallons, difficult to prove I'm sure but I would assume they'd be happy to replace a faulty unit.

Ike Mouser
(isaac.mouser) - F
million on 10/26/2010 13:26:30 MDT Print View

they may gurantee a million, but do you really expect this filter to last the rest of your hiking life or do you see yourself purchasing anothet at some point in the future?

Brad Groves
(4quietwoods) - MLife

Locale: Michigan
Re: Re: Pre-filters ? on 10/26/2010 13:32:46 MDT Print View

You CAN field backflush, but I've found that the best way is to rig a second hose w/quick connect &, basically, decided it's instead easier to just run the prefilter. I forget exactly how far I got last time before the flow rate got annoyingly slow, but I think it was around 6 days filtering for 2.

My field backflush set-up used another hydration hose/fitting, quick connects, second platy. Hook up for reverse flow, sometimes stand on platy to generate enough pressure for backflush. Usually not needed. Or I could eliminate the extra components.

For shorter trips could probably do away w/backflush and prefilter, BUT since my water source is filled straight from the river and has all the included floaties (leaf detritus, etc) I figure the prefilter is easy, not a big weight issue, & might save me a little headache.

Eric Lundquist
(cobberman) - F - M

Locale: Northern Colorado
Re: million on 10/26/2010 13:35:11 MDT Print View

It may very well last the rest of my hiking life. Although, as ULer I'm always looking to reduce my base weight and at 6oz total I'm sure they'll come up with something else that will serve the same function at a lighter weight in the coming years. For now I feel that this is one of the better systems out there and is relatively cheap when you compare the other options. If it broke due to my negligence I would promptly go out and buy a duplicate model without reservations.

Edited by cobberman on 10/26/2010 13:35:58 MDT.

Ike Mouser
(isaac.mouser) - F
sawyer on 10/26/2010 13:37:21 MDT Print View

Are you guys using sawyer filters or purifiers?

Eric Lundquist
(cobberman) - F - M

Locale: Northern Colorado
Re: Sawyer Gravity Filter on 10/26/2010 13:42:47 MDT Print View

I'm using a Sawyer In-line Water Filter which is an older model than was mentioned in the OP and sold at REI.

Ike Mouser
(isaac.mouser) - F
filter prototype on 10/28/2010 08:42:30 MDT Print View

So here is the final mockup of what I want my filter to look like once its completed. I stole the off-center fitting idea from the platypus(or is it some other brand?) that I saw. The combination off-center fitting + 1 micron pre-filter bag + carbon filter, should squeeze as much life out of the sawyer as possible without slowing down the flow too much. I saw a video of the biodiesel bags in action on youtube, they literally let the water flow through as if it was not there.

I like the system because the parts that wear out are easily replaceable. Replacement biodiesel fuel filter bags are cheap, especially if bought big and cut down to size($1 or so), im sure they will last quite awhile(2 weeks maybe). Activated carbon is cheap in bulk as well. I would just stick an aquamira frontier pro in there and ditch the micron bag and casing with activated carbon, but I’ve used them for 2 years now and usually have to replace them fairly quickly. They are more prone to clogging because of their design.

Thoughts? Suggestions?

On a related note. Where would is store such a prefilter bag when im done with it? Im thinking a zip lock would promote the growth of all kinds of things. Maybe on the outsize of a pack in slightly opened ziplock to allow moisture to evaporate?

filter prototype