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Maybe one day
02-17-2013, 20:57
I purchased an Sawyer Membrane Filter. I am all in on the technology as I have engineered some similar systems for municipal water systems on a much larger scale (on the order of 10 Million Gallon/day filtration rate..its about time it is available to the hiker). Some experience to note:
1. The bladders that come with the filter are difficult to fill in a creek when new. They are relatively stiff and the water will not easily flow into the bladder to fill. Water flowing over a rock or log may work better, but a pool doesn't work at all. I found a spot with good flow and it was still difficult to fill the bladder. A thin plastic rigid water bottle may be a better solution than the bladders.
2. Upon use, the bladder retains water, which I expected. However, even with the spout closed and covered, it still manages to drip some. I was on a day hike and had the bladder in a small pack with a jacket. The jacket was very wet at the end of the hike. Thus you would want to carry the device appropriately to protect from freezing and keep other things from getting wet.

With regard to how well it worked, who knows? I have not gotten sick, but the water appeared to be a good source (Chatooga River headwaters in NC..probably would have been fine without a filter) There is really no way to know if your filter works - only if it doesn't work!

-Maybe One Day!

Maybe one day
02-17-2013, 20:59
Correction - On item 2, the filter unit attached to the bladder retains water and leaked....should have proof read a little better

leaftye
02-17-2013, 21:05
Many of us with the same filter will use some sort of cup to fill up the bladders. I prefer using the bottom of a Smartwater bottle.

Did you get the new or old bladders? The front of new bladders are mostly blue and are supposed to be tougher.

If you don't already know, roll rather than squeeze the bladders to get the most life out of them.

Maybe one day
02-17-2013, 21:10
I am pretty sure it is the new bladder style. They are mostly blue in color. Thanks for the tip on filling the bladders and rolling the bladders.

4Bears
02-17-2013, 22:54
Just a thought, why couldn't you use the empty bladder to force some air through the filter to chase most of the water out of the filter? I reallize that involves an extra step when using, but in cold weather it might help prevent some freeze damage and leaking.

Coffee Rules!
02-18-2013, 05:28
I loved the filter and the ease of use as far as squeezing/rolling the bags to get the water through, but yeah, filling the bags sucked in a huge way. I found myself wishing I hadn't left my pack 200 yards away uphill by the shelter. I would've gotten out a cup and done as leaftye mentioned.

Hairbear
02-18-2013, 06:12
I would sell the one i have. Seems to be a pain in the keester trying to squeeze water out of it with finger/joint issues. When its cold you have to worry about freezing. A person on hf posted that you can see if your filter is working right by adding food coloring to the bag,if the color makes it through the filter its not working .

leaftye
02-18-2013, 09:31
When its cold you have to worry about freezing.

That's a concern with every filter.


A person on hf posted that you can see if your filter is working right by adding food coloring to the bag,if the color makes it through the filter its not working .

That's wrong.

Odd Man Out
02-18-2013, 10:25
...A person on hf posted that you can see if your filter is working right by adding food coloring to the bag,if the color makes it through the filter its not working .


...That's wrong.

Definitely wrong.

mn_scout
02-18-2013, 10:44
I keep my squeeze filter in a 1 quart ziploc. The output end of the filter is covered so it does not get contaminated and I don't worry about wetness from the filter. I use the baggie to scoop water out of any water source, standing or flowing.
Also, shaking the filter after use gets rid of most water left in it.

Two Paw Dog
02-18-2013, 13:57
I take the my Sawyer filter out of the Sawyer bottle and connect it to the output of the Sawyer cap and and screw the cap on a Nalgene bottle of water i want to filter. The filter is now on the outside of the bottle of water to be filtered. Turn the Nalgene bottle upside down and now it works as a gravity filter and i can filter several bottles at one time.

Maybe one day
02-18-2013, 18:51
I keep my squeeze filter in a 1 quart ziploc. The output end of the filter is covered so it does not get contaminated and I don't worry about wetness from the filter. I use the baggie to scoop water out of any water source, standing or flowing.
Also, shaking the filter after use gets rid of most water left in it.

Good idea. I will try that one next time.

Maybe one day
02-18-2013, 18:54
A person on hf posted that you can see if your filter is working right by adding food coloring to the bag,if the color makes it through the filter its not working .

One filter manufacturer does recommend this - Micropur - avery good but very heavy filter and pump. Manufacturer even provides blue water coloring. I am not sure if it is the end-all/be-all test for other filters though.

Loneoak
02-18-2013, 23:06
Love mine, I did however cut the top of my smallest bag to use as a scoop for water. If you didn't know it already, they will thread onto a Smart Water bottle.

SunnyWalker
02-19-2013, 00:05
Aqua Mira.

Aquaman12
02-19-2013, 01:02
Does anyone else use theirs inline on their drinking tube of the hydration system?

Odd Man Out
02-19-2013, 01:06
One filter manufacturer does recommend this - Micropur - avery good but very heavy filter and pump. Manufacturer even provides blue water coloring. I am not sure if it is the end-all/be-all test for other filters though.

Did some searching on this. Mircropur seems to be the brand name for the purification chemicals sold by Katadyn. I found no references to dyes sold by them. I did find several on-line reports of a blue dye sold along with First Need Filters, by General Ecology. However, I couldn't find any info on their web site about a dye or it's specifications. I wonder if they were selling Blue Dextran (or something like that), which is glucose polymer bead with blue dye attached. It is used to determine the void volume of a exclusion get chromatography column (i.e. gel filtration). These beads have a size of 2 million kDa and thus might be removed by a filter. However ordinary food coloring will not behave this way as these are small dissolved molecules.

Maybe one day
02-20-2013, 00:17
You are correct on the filter/manufacturer being First Need by general ecology - I stand corrected. It is a very good filter albeit rather heavy. The instruction packet that comes with the filter and replacement cartridge does recommend the blue colorant that comes with the filter. I do not know the technical details of the colorant that is provided. Good info to know that regular food coloring will not suffice. Based upon your statements you appear to be a subject matter expert. Thanks for the input!

Odd Man Out
02-20-2013, 00:28
You are correct on the filter/manufacturer being First Need by general ecology - I stand corrected. It is a very good filter albeit rather heavy. The instruction packet that comes with the filter and replacement cartridge does recommend the blue colorant that comes with the filter. I do not know the technical details of the colorant that is provided. Good info to know that regular food coloring will not suffice. Based upon your statements you appear to be a subject matter expert. Thanks for the input!

I wonder if they still provide the dye since I can't find anything on their web page about it. It does look like a good filter. They even advertise that it has small enough pore size to filter out viruses. Not many filters can do that. I saw they also had an attachment to hook up a gravity system. I wonder if they will be going in that direction like many of the other makers are.

leaftye
02-20-2013, 00:48
Berkey also uses a food coloring test. Their filters might actually be decent, but I hate how they use marketing gibberish instead of giving honest technical answers. That sure works great with feeble-minded survivalists though. What they won't say is that their filters will block food coloring that uses particulates instead of a dye that actually dissolves. That's going to work with other filters too. Looking at wikipedia, natural red food coloring should work with this test. Artificial red and blue food coloring should not work.

Indiana Camper
02-20-2013, 09:05
Hum. Guess I'm feeble-minded because I do own two Berkeys and do want to survive....

Odd Man Out
02-20-2013, 11:42
Berkey also uses a food coloring test. Their filters might actually be decent, but I hate how they use marketing gibberish instead of giving honest technical answers. That sure works great with feeble-minded survivalists though. What they won't say is that their filters will block food coloring that uses particulates instead of a dye that actually dissolves. That's going to work with other filters too. Looking at wikipedia, natural red food coloring should work with this test. Artificial red and blue food coloring should not work.

I had not seen these before. They use filtration combined with adsorbtion (like charcoal filter) and ion exchange (like a water softener). These latter two will definitely remove dyes (even some food coloring if the molecules are ions). In fact in your chemistry lab you may recall adding "decolorizing charcoal" to your solutions to help purify your product.

However, any filter that relies on adsorption and ion exchange will have a limited life. Once they are used up they must be replaces (which is why it would be a good idea to have a way to test them). As long as a filter can be back flushed to remove particles, in theory it can be used indefinitely, which is why the Sawyer filters have a 1 million gallon guarantee. They rely only on pore size-based physical filtration which is why the same dye test would not be reliable. It is also why they are popular with thru hikers - you don't need to worry about how long your filter will last.

I saw they advertise that their filter remove fluoride ions. I live in a town that has a monument to public water fluoridation. Hmmm?

HooKooDooKu
02-20-2013, 17:23
When its cold you have to worry about freezing.That's a concern with every filter.
Not quite correct.

The MSR SweetWater filter is freeze and impact safe.

Interestingly enough, MSR doesn't point that out on their web site. I'm guessing that's a marketing choice so that they don't point out this particular weakness of their other products.


I suspect that the SteriPEN also does not have to worry about freezing conditions.

leaftye
02-20-2013, 18:10
Not quite correct.

The MSR SweetWater filter is freeze and impact safe.

Interestingly enough, MSR doesn't point that out on their web site. I'm guessing that's a marketing choice so that they don't point out this particular weakness of their other products.

Good to know.

I checked the Sweetwater manual and as you said, it doesn't mention freezing. I checked the manual for my MSR Autoflow, and it warns not to freeze the filter.


I suspect that the SteriPEN also does not have to worry about freezing conditions.

It's not a filter.

kidchill
02-20-2013, 18:51
I used a Sawyer squeeze for my thru and it worked more then well. A few things. The Mylar bag sprung leaks before I hit 300 miles. I used a platy bladder and never looked back. Also, with a platy bladder you can throw an ultralight carabiner on the bottom end and hang it to use as a gravity filter. This works wonders when it's late and you need to make your home for the night. Most of the time I would hang it from my trekking poles sticking out of the ground. When you're done with the filter, remove it from the bladder, leave the spout open and wing it around like you're trying to get ketchup out of a bottle...this will remove most of the water. Close the cap, and put the cover on it. Then I would just roll it up with platy bladder and shove it in an open ziploc bag in a side pocket of my pack. There's always gonna be a little water from the filter or the bladder. Also, I would have my Ti coffee cup hanging from the outside of my pack. If I couldn't get the stream water to flow into my bladder, I just bailed it in there...It's a great filter and other then the mylar bag breaking, the only problem I had was I let it freeze one night...It was my bad, so I really can't complain.

Odd Man Out
02-20-2013, 20:26
I got an e-mail from the General Ecology Company, makers of the First Need Filter. They report the content of their dye used to test the integrity of their filter to be FD&C Blue #1 and FD&C Red #40 (i.e. food coloring). I presume this works because their filter (like the Berkey filters) use and adsorption and/or ion exchange system along with physical filtration. This is why they are effective at filtering colored dyes. It is also why their filters have a limited life-span (# of gallons filtered) before they have to be replaced. This also makes a test for filter effectiveness more critical (so you know when the filter is used up). The dye test will not work to test the integrity of filters that use only physical filtration based on pore size (such as a Sawyer Filter). My earlier speculation that a dye-linked to to a polymer might work for testing physical filters did not pass the test. In the lab today I found that Blue Dextran (average MW-2,000,000 g/mol) goes through a 0.45 micron filter. I hope people find this useful.