#267380 - 02/14/14 09:31 PM
Water purification, "LifeStraw Family", on sale
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Pooh-Bah
Registered: 03/13/05
Posts: 2322
Loc: Colorado
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On sale for $49.95 with free shipping as of 2/14/2014 I'm sure I've mentioned this product here before, but it's on sale again, cheaper than I've seen it on sale before. I've had two of the individual sized LifeStraws for a couple of years now, but this price prompted me to buy the larger version too. LifeStraw Family (large volume water purification - bacteria, protozoa, virus): http://eartheasy.com/gifts/camping-and-o..._eid=dc9fed8cc9
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#267382 - 02/14/14 10:25 PM
Re: Water purification, "LifeStraw Family", on sale
[Re: haertig]
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Enthusiast
Registered: 02/14/08
Posts: 301
Loc: Croton on Hudson, NY
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thx for the tip. bought one, along with the individual lifestraw.
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#267387 - 02/15/14 04:01 AM
Re: Water purification, "LifeStraw Family", on sale
[Re: tomfaranda]
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Enthusiast
Registered: 02/01/14
Posts: 310
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Not a life straw, but I bought a 30 gallon Frontier Filter for a belt PSK. Someone told one of the survival guys I follow that it's very ineffective and that I should use the Aqua Mira tabs in conjunction with it. This seems to have been a waste of money if I have to use tabs. And there's no indicator for when the filter has reached the 30 gallon mark. Any thoughts or suggestions on this?
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#267390 - 02/15/14 05:24 AM
Re: Water purification, "LifeStraw Family", on sale
[Re: haertig]
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Rapscallion
Carpal Tunnel
Registered: 02/06/04
Posts: 4020
Loc: Anchorage AK
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Y'all should really check out the Sawyer filter system. http://sawyer.com/products/sawyer-mini-filter/I've been buying these for $20 a piece. They are lightweight and take up as little space as the lifestraw, but look at how much water they will process, and their filter level is superior to the lifestraw. For the money, this is a much better deal. You can use it just like the lifestraw, or you can screw it onto the collapsible bag, or even onto a soda bottle. These units are the bomb. Watch their video Here: http://sawyer.com/videos/sawyer-mini-water-filter/This may be the best item I've ever recommended for survival.
_________________________
The ultimate result of shielding men from the effects of folly is to fill the world with fools. -- Herbert Spencer, English Philosopher (1820-1903)
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#267392 - 02/15/14 08:58 AM
Re: Water purification, "LifeStraw Family", on sale
[Re: benjammin]
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Pooh-Bah
Registered: 03/13/05
Posts: 2322
Loc: Colorado
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That Sawyer filter looks interesting. Comparing it's specs to the LifeStraw Family specs, things don't make sense to me.
For one, how can a 0.1 micron filter (the Sawyer) claim to filter MORE bacteria and protozoa than a 0.02 micron filter (the LifeStraw Family)? It's pore size is 5 times larger. I could maybe understand that claim if the 0.1 micron filter was much larger, thus having a greater total filter area that water has to pass through, although even then the claim would be suspect. But the Sawyer is just the opposite - it's much smaller than the LifeStraw Family. Maybe it takes so long for the water to get through the filter that the pathogens die of old age and are thus rendered harmless.
My hunch is either the LifeStraw or the Sawyer is good, not great, but fine for emergency use. But both of their claims have to be taken with a grain of salt. Especially the amount of water they will filter. At its claimed 100,000 gallons, that little 4 inch Sawyer could supply an entire town for a multi-month emergency.
For backpacking use, or keep-in-the-car survival kit use, I'd go for the Sawyer, hands down, due to it's size and incredibly cheap price. For home use or bug-out (with a vehicle) use, I think the LifeStraw Family would get my vote. I would like to see some independant reviews of these filters from a qualified lab. I did a little searching on Google for this, but only found non-formal testing done by bloggers and outdoor writers, not scientists with the proper training and equipment.
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#267401 - 02/15/14 08:44 PM
Re: Water purification, "LifeStraw Family", on sale
[Re: LesSnyder]
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Pooh-Bah
Registered: 03/13/05
Posts: 2322
Loc: Colorado
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...the specs on the LifeStraw off an Amazon ad claim .2 micron not .02 micron, but possibly a typo... The LifeStraw Personal is a 0.2 micron filter, and claims to filter 264 gallons of water. The Sawyer is a 0.1 micron filter and claims to filter 100,000 gallons. That's 400x what the Personal claims, and the Sawyer has a smaller pore size. That claim is a little hard to believe, but maybe true. I guess if you backwash if many many many times... The Sawyer is much smaller than the Personal. The Personal and the Sawyer do not do viruses. They cost the same. The LifeStraw Family (the one I was talking about in the initial post in this thread) is a 0.02 micron filter and claims to filter 18,000 liters of water. The Family does do viruses. The Personal would be a competitor for the Sawyer, the Family is really a different class of filter.
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#267402 - 02/15/14 09:15 PM
Re: Water purification, "LifeStraw Family", on sale
[Re: haertig]
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Enthusiast
Registered: 09/10/08
Posts: 382
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That Sawyer filter looks interesting. Comparing it's specs to the LifeStraw Family specs, things don't make sense to me.
For one, how can a 0.1 micron filter (the Sawyer) claim to filter MORE bacteria and protozoa than a 0.02 micron filter (the LifeStraw Family)? It's pore size is 5 times larger. I
How can they claim? Because they have lab reports just like the other guys to make claims? I assume it has to do with the micron rating. The absolute rating, of cut-off point, of a filter refers to the diameter of the largest spherical glass particle, normally expressed in micrometers (mm), which will pass through the filter under laboratory conditions.
The nominal rating refers to a filter capable of cutting off a nominated minimum percentage by weight of solid particles of a specific contaminant (usually again glass beads) greater than a stated micron size, normally expressed in micrometers (mm). I.e. 90% of 10 micron.
Micron Ratings: Absolute Microfiltration vs. Nominal An absolute pore size rating specifies the pore size at which a challenge organism of a particular size will be retained with 100%
A nominal pore size rating describes the ability of the filter media to retain the majority of particulate at (60 - 98%) the rated pore size.
However there's microns and then there's MICRONS. These ratings are published by the manufacturers variously as "nominal," "absolute" and "average" or often, with no explanation. "Nominal" is the confusing one. To keep it simple, consider that this refers to the size of the largest pore in the filtering medium. However, organisms larger than this size will make it through the filter because they are not hard or rigid like ball bearings or needles, but rather can, and do, deform like gelatin or a sponge to get through. This leads to the "absolute" rating which means exactly what it says, it is absolutely the biggest critter that can pass through, period. This is the most accurate type of rating because there is no ambiguity. "Average" means that some organisms smaller than that won't pass, but some larger than that will and you have no idea what the limits are. Bear in mind that this is only part of the story since some filters utilize other methods to interdict and destroy smaller pathogens
2004 Nominal Rating - Expressed as a percentage of retention by micron size (For example, 90% of X Microns)
Absolute Rating - Expressed as the maximum sized particle which the filter will pass (All particles of X Microns size). A general rule of thumb is to multiply the nominal rating by 5 to obtain the more reliable absolute rating.
A leading water industry association defines nominal to mean 85 percent rejection at the stated micron rating and at the recommended flow rate. Absolute provides a much stricter efficiency standard for the filter media, typically 98-99% percent rejection rate. The ultra-pure water industry even defines absolute as a 99.99 percent (4-log) reduction, or greater. However, independent validation might be in order for filter manufacturers making this claim.
What do you mean by 0.1 and .02 micron absolute?
Many other filters list nominal or average pore sizes which leave the possibility of harmful pathogens to pass through. By claiming absolute microns there are no variances in pore size on our filter membranes. At 0.1 and 0.02 micron absolute these are true barrier filters so there is no questionable time period whether the water is safe to drink.
So , always compare the percentages/log reductions, because that is what the lab tests proved. Absolute micron is better than other microns, this explains the difference in lab tests. Lifestraw does not advertise absolute micron (which means not-absolute), and the test results reflect this (they report different percentages) See also Re: Emergency water (gallons, EPA LT2 ESWTR )At its claimed 100,000 gallons, that little 4 inch Sawyer could supply an entire town for a multi-month emergency. I assume the difference in gallons is the quality of the backflushing device. LifeStraw seems to use squeeze bulb, where as Sawyer provides a syringe; A syringe should produce significantly more pressure. Thinking about it, this could explain the difference in the bacterial counts -- if one filter gets backflushed cleaner than the other -- the other filter will be scummier For USA/Europe i would definitely go with sawyermini -- $25 at REI brick and mortar store If worried about viruses, say you're filtering hospital sewage, then household bleach after filtering to kill the viruses -- only 13 minutes needed to inactivate viruses see below Table 9. MicroFiltration and UltraFiltration Studies Documenting Bacteria Removal Efficiency Hollow Fiber Membranes .2 and .1 can remove some viruses . .03 has very good virus removal properties
North America vs. Third World Countries In North America we do not have concerns about viruses in our water. They simply cannot survive. Viruses derive from contaminated human sewage and die shortly after entering a body of water. In Third World countries outbreaks have occurred due to poor treatment of sewage. Sewage without viruses can be handled by the PointONE™ filter. The only viruses with the potential to survive in water are hepatitis (which is rare) and Polio (which is extremely rare). You can contact CDC for information on virus outbreaks in areas for which you are traveling.
CDC - Effectiveness on Pathogens - The Safe Water System Inactivation of Viruses 12.72 Time of chlorine exposure (min) 0.5 Concentration of chlorine (mg/L)
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#267407 - 02/16/14 04:40 AM
Re: Water purification, "LifeStraw Family", on sale
[Re: EMPnotImplyNuclear]
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Geezer in Chief
Geezer
Registered: 08/26/06
Posts: 7705
Loc: southern Cal
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Interesting thread, but it just makes me want to boil (the water, that is).....
_________________________
Geezer in Chief
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