I've seen the suggestion to filter food coloring (in water), if color gets through then it has failed.Originally Posted by squeezebox
That is what the manual says for my first need water filter.
"Blue Dye" test:
Put two drop's of blue food coloring in a small container of water. Pump colored water through canister as shown. If the purified water is still colored, even faintly, the internal" canister matrix has most likely been damaged and The Canister Can Not Be Relied Upon Under This Condition And Must Be Replaced.*
I'll tell you all what: I'll go try it with my Sawyer (which has never been frozen) and let you know what happens.
Edit: Results of test. Keep in mind these results do not mean the filters are bad. The First Need is the gold standard of filters. The first need in the test is 20 years or so old and has had the crap used out of it. The results show you cannot use food coloring to test the sawyer, or the hiker pro. The hiker pro in the test has an almost new cartridge and has never been frozen.
First Need Before:
First Need Before.jpg (800x600).jpg
First Need After:
First need after.jpg (800x600).jpg
Sawyer before:
Saywer Before.jpg (800x600) (2).jpg
Sawyer after:
Saywer After.jpg (800x600).jpg
Hiker Pro before:
Hiker Pro Before.jpg (800x600).jpg
Hiker Pro after:
Hiker Pro After.jpg (800x600).jpg
Last edited by bfayer; 02-10-2014 at 15:18. Reason: test results
That is for General Ecology's First Need. The same test may not apply to the Sawyer. This is a question that you don't want a bunch of cyber hikers giving total clueless answers to. I would give Sawyer a call and get a definitive answer.
Lonehiker (MRT '22)
I use the Sawyer Squeeze Filter (the larger one because of the "snap top" on the drinking end). I have an empty smart water bottle as my "clean bottle" and only filtered or clean water goes in here. I also carry the pouch for "dirty water" and have an empty Gatorade bottle if I need to carry extra water. If I carry the Gatorade bottle, filling the pouch is super easy as I just pour the water in. I often carry the empty Gatorade bottle just for this purpose (plus extra water for camp).
Yes, this one came up before. That filter has an adsorption filter (like charcoal) that will filter dyes. The Sawyer has a filter based on pore size and will not filter molecules, even when working correctly, since dye molecules are much smaller than the size cutoff for the filter, which is designed to remove things the size of bacteria or larger.
With these particulate filters, you may notice that air does not go through your filter very well. One trick to getting a good flow rate is to get the air bubbles out (rather than just squeezing harder). If you notice that air suddenly is going through your filter easily, this could be a sign that it has been compromised. I know this test works with micron sized pore filters I have used in labs, however, without some testing, I wouldn't be too confident that this test will tell me that the filter is good or bad. Maybe someday I could do that.
Bold mine
However this is not one such case to prove your point, but perhaps quite the opposite. My statement, though incorrect for this application was never stated as definite, but has lead others to post, and actually test, and give a answer that is helpful to the OP as well as clarify where my post would be applicable and why it is not in the case of the OP. In other words a system were people can openly communicate and help each other is a darn great way to find answers.
The FAQ section on the Sawyer website says:
How do I care for my filter during freezing weather?
Before initial wetting
Filter is safe from freezing temperatures if it has never been wetted.
After initial wetting
While there is no definitive way to tell if a filter has been damaged due to freezing, Sawyer recommends replacing your filter if you suspect that it has been frozen.
During trips
If you are in freezing temperatures we recommend that you store your filter in your pocket or close to your person so that your body heat can prevent freezing. THERE IS NO WARRANTY FOR A FROZEN FILTER
Your post got me to thinking, and I needed to PM my filters anyway. If you call Sawyer they will only tell you "If it freezes throw it away" they will not tell you how to test it, and they will not test it for you. Because I use my filter for other peoples kids, it is always good to have a a way to test the filters. I figured it was worth a try.
I think the test showed three important things:
1. You cannot use the food coloring test for the sawyer or the hiker pro.
2. The First Need filter really is the gold standard of water filters.
3. Food coloring particle size is smaller than bacteria. Who knew
I would not have tested the filters if it was not for your post.
If I treat water I use bleach, one drop per cup (8oz), if it's up in the hills away from people I dont treat it. I use Clear Eyes bottles as a container.
2014_02110001.jpg
You should replace your bottles with opaque bottles. Bleach degrades very quickly when exposed to sun light, and I mean very quickly. It also degrades with time in the dark, and that includes sitting on the shelf in the laundry room.
http://www.sciencedirect.com/science...4313549290232S
Without testing you have no way of knowing if there is enough free chlorine to disinfect your water. All you can do is use NEW bleach, keep it in opaque bottles and replace it often.
There is a reason bleach is not sold as water purification for hikers, and it's not because of corporate greed.
Last edited by bfayer; 02-10-2014 at 18:35.
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