Jun 29, 2008 at 5:30 pm #1229896
@einsteinLocale: Big Apple
I see a carbon stage in filters is used mainly for improving "taste," but it's also implied it removes pesticides and herbicides (assume trace amounts). I have a few filters with carbon stages, and in areas where there could be run-off from farms or inorganic pollution, the carbon makes me feel better (and yum, the water tastes better–I think).
But not all filters have carbon stages, and certainly those using chemical or UV treatment (which I also do) don't get the benefit of carbon filtering.
So what's the lowdown–marketing gimmick, or necessary near farms or in populated areas, or the amount of carbon filtration offered in handheld filters does little more with than without and is typically unnecessary?Jun 29, 2008 at 10:04 pm #1440768
@halfturboLocale: Northernish California
I think you've outlined it well–if you're concerned about organics, carbon makes good sense. To be effective, it needs an adequate amount of contact time, which implies matching the flow with the correct amount of carbon. I don't know which filter makers might test their products for those parameters.
For folks who travel in alpine areas (e.g., western US mountains), organic contamination is usually of no concern, and carbon would add no health benefit. It can improve the taste of stagnant or slow-moving water, though.
You have to be careful about drying carbon between uses, since wet it can become a great home for bacteria and mold.Jun 29, 2008 at 11:16 pm #1440774
Carbon, even in relatively small quantities, is effective in absorbing chemicals and odors, and improving the taste of the filtered water.
If your water is at risk for human or farm pollution, make sure you are killing all the nasties – i.e. use a purifier or chemical treatment that will take care of viruses and bacteria.
I personally use a prefilter cloth (if necessary), then treat with chlorine dioxide, and then will filter through a carbon filter if taste or chemical contamination is a concern.Jun 30, 2008 at 12:49 am #1440778
@rcaffinLocale: Wollemi & Kosciusko NPs, Europe
> I see a carbon stage in filters is used mainly for improving "taste," but it's also implied it removes pesticides and herbicides (assume trace amounts).
Correct. Especially agro-chemicals.
That said, unless you know you will be having a problem with those sorts of chemical, unnecessary imho.
Brown colour, as in tannin – heat, add milk and sugar: tea. :-) (ie Harmless.)Jun 30, 2008 at 3:16 am #1440786
@mad777Locale: South Florida
Timely question for me Simon. Just earlier this month there was an indepth discussion on treatment methods. As a result I am adjusting my method. I have been a Steripen user for some time, using a 1L wide-mouth Nalgene soft-sided canteen.
In this forum I learned of a stainless steel mesh, skrew on coffee filter made by GSI. I will now use that as my prefilter. I have also added an ounce of charcoal in the coffee filter. I simply sewed a little bag of noseeum netting and I get he charcoal from an aquarium shop.
I will dip the canteen, with the coffee filter and charcoal attached, then remove the coffee filter and use my Steripen Adventurer.
That's my new system to handle sediment, chemical contamination and biological contamination! I will put it through an extensive test in 2 weeks as my family & I hike across the White Mtns. of New Hampshire.
The weight is:
Steripen Adventurer 3.6 oz
GSI coffee filter 1.7 oz
Charcoal in net bag 1.0 oz
Nalgene wide-mouth 2.0 oz
Total weight 8.3 oz including drinking container with all bases covered and no pumping. Just add water.
Of course, I always carry a few chlorine dioxide tablets for back-up.Jun 30, 2008 at 7:40 pm #1440927
@einsteinLocale: Big Apple
Good info and good advice, thanks all.
Jason: what carbon filter do you use?
Michael: let us know how that carbon filter works on your trip.
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