Like a lot of people here, I seem to be constantly searching for the best water filtering system. I used to use a Hiker Pro (and still have it), then bought a Frontier Pro to make a system (like Jason Klass'), THEN went out and bought a Sawyer filter AND have Aquamira drops.

Question #1: I'm making a charcoal filter to go after the Sawyer FILTER or to use with the Aquamira. I bought some activated charcoal at Petsmart. Is activated charcoal for fish tanks just activated charcoal? Meaning, is there any difference to buying AC specifically marketed for a drinking water filter vs. for a fish tank filter?

Question #2: I already have the Aquamira drops, so I will go through those, but I'm wondering why more people don't seem to use the MSR Sweetwater drops (or Klearwater) that come in one bottle and require no mixing. Just curious.

> is there any difference to buying AC specifically marketed for a drinking water filter vs. for a fish tank filter?
The biggest difference is probably in the marketing spin and the retail price.
Fish are very sensitive to some chemicals (hence the charcoal filter), so the fish tank stuff should be fine.

Cheers

Activated charcoal traps bad tasting stuff like organics but doesn't do anything for Giardia?

It's just for aesthetics, not for health?

Why bother?

Maybe removes chlorine?

Somewhere I was reading about someone developing water filtering for third world countries. They were attempting something like activated charcoal in a tea bag. It was supposed to trap parasites, viruses, and bacteria. A few cents per bag. Presumably very lightweight. It would be nice if something like that became available.

RE: question 2, I just premix my Aqua Mira the night before heading out on the trail for 2-3 day trips. Longer trips, you can premix a day or two's worth at a time at camp at night.

"RE: question 2, I just premix my Aqua Mira the night before heading out on the trail for 2-3 day trips. Longer trips, you can premix a day or two's worth at a time at camp at night."

No. Do not do this. It looses potency after 5 minutes or so. After 5-6 hours, it is just a bit of salt in the water.

"No. Do not do this. It looses potency after 5 minutes or so. After 5-6 hours, it is just a bit of salt in the water."

Someone who has studied this, like scientifically and such, would disagree with you.

Always willing to learn...
???

Douglas,
I need some studies, reports, where is the info you allude to?
Thanks!
jdm

I spent several hours searching about, and found this on this web site:
http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=3601
Not exactly scientific, but...

In response to a query posed to McNett by Scott Ashdown, AKA waterloggedwellies:


I asked the question of McNett, the makers of Aquamira whether it could be premixed before a trip. Here's their reply by email:

Dear Scott,

Thank you for your email and question regarding our AquaMira Water Treatment.

The two solutions must be mixed at the time of use. The ClO2 solution that is created by mixing the two liquids is not stable over long periods of time and will not be effective if mixed in advance of your trip. The website www.backpacinglight.com has a selection of smaller dropper bottles.

You may be interested to learn that we have created a tablet form of AquaMira that is currently going through the EPA registration process. This new product is expected to be available by the end of this year.

Please let us know if you have any further questions or concerns.

Kind Regards,

Customer Service

McNett Corporation

Edited by jamesdmarco on 01/13/2011 03:22:35 MST.

James,

I'm not a scientist, I have no studies or reports.

I did not sleep at a Holiday Inn Express last night.

I'll continue premixing mine for weekend trips.

If I get sick, I'll let you know so you can say "told you so!" ;-)

Douglas,
I am a scientist. (Though, I am retired.)
Ha ha,Holiday Inn Express?? Nope, never been there.
Feel free. Nobody ever needs to listen to me, anyway.
Only 2 in 3 get sick with Gardia. Crypto is much more rare. No need to tell me when you have a case of the "scoots".

It seems I was wrong. Sorry all.
The AM drops remain effective for some time after mixing. No one seems to be able to pin down the time, though...probably depends on the temp. Mixing a days worth in advance seems to leave the solution mostly effective, though. It can be effective for longer if kept cold.

Edited by jamesdmarco on 01/15/2011 13:25:08 MST.

@Jerry: the AC just removes chemicals from the water, but doesn't play any part in actually filtering bacteria/viruses in the water. I was following Ike Mouser's thread about using household bleach (sodium hypochlorite) and then using the AC to improve taste and remove the chlorine.

For my question #2 above: I should have read a little bit more. It turns out the MSR Sweetwater Purifier liquid is a 3.5% sodium hypochlorite solution, not chlorine dioxide. Basically, household bleach. I think that Klearwater is the only pre-mixed chlorine dioxide solution on the market (something I've never used and can't comment on).

Btw, there is some noise on other threads right now about pre-mixing AM liquid before a trip, how much to use in different parts of the country/with different water sources, etc. For me, more than anything, this is just my latest "gear distraction" and whether I'll actually use any of it remains to be seen! It is fun learning and playing around with new stuff!

Are there any filters certified to remove pesticide residue from agricultural runoff? I'm guessing this isn't a concern where a lot of you hike (the western mountain ranges), but here in the midwest, water quality is often dubious from sediment and ag chemicals as much as from biological contaminants.

ETA: Right now I use filter paper and micropur. I would like to find an all-in-one filter that I can use for a gravity setup.

Edited by spelt on 01/15/2011 12:19:34 MST.

I too bought a jar of aquarium AC (pellets about 1/8" dia x 1/4") at Petco; in my case it was to make some AC filters for my SteriPen. I suggest breaking the pellets into small pieces as AC works by surface area. (One gram has about twice the surface area of a tennis court). But if you make the pieces too small, expect slower flow rates in gravity systems. My current setup is a Dole Fruit Cup with holes in the bottom, lined with a coffee filter filled to the brim with AC, then covered in no-see-um netting. The Dole cups have fluted sides to allow air to escape when used on top of a Nalgene Cantene or similar. (Rinse the carbon well so there are not AC particles when you use it for drinking water.)

I was always curious about latency (how long water needs to be in contact with the AC to remove x% of different chemicals/odors) but could find no specifics. Commercial backpacking filters with an AC stage seem to use a very fine pellet (like the fragment of a 0.5 mm mechanical pencil lead), but most rely on pump pressure to accelerate output (which probably reduces latency). I remember buying some AC under the Katadyn brand name a few years ago for a gravity system, and throughput was very slow.

So I'm not sure if I have it right, as my treated water still has a similar color cast and organic odor as untreated water, but I haven't gotten sick...

activated charcoal may remove pesticides

Katadyn Hiker has activated charcoal

Granular activated carbon (GAC) can remove some pesticides along with chlorine and iodine. A GAC element is found inside the MSR MiniWorks.

Lots of good info on contaminants and pathogens and treatment systems can be found at www.backcountrywater.com. There is a section on chemical contaminants and how well GAC removes them.

Edited by BackcountryRob on 01/17/2011 03:38:01 MST.