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Your opinions: Best filtration systems

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Offline Flash

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Re: Your opinions: Best filtration systems
« Reply #15 on: September 25, 2013, 04:15:48 PM »
I'm surprised at how many use Aquamira drops.

If you haven't tried the tablets yet, you might want to. They are soooo fast to deploy. Whip out the swiss army knife scissors, cut the small, square, individual hermetically sealed tablet-pouch, drop in container, shake, stow away, keep on hiking...

And, yes, the bandana(s) only come out if needed -- I don't mind a few minor flecks either.
Yep. Same great story on ease of use applies to the MicroPur tablets as well.  :)

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Offline sleepy

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Re: Your opinions: Best filtration systems
« Reply #16 on: September 28, 2013, 10:11:39 PM »
An old-timer told me once that you can put alum in a silty bucket of water and it will clear up in minutes..
I know a guy sprayed wd40 on his wrists for his arthritis.
It's never too late to be what you might have been-Geroge Elliot

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Offline Lance

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Re: Your opinions: Best filtration systems
« Reply #17 on: September 28, 2013, 10:22:35 PM »
An old-timer told me once that you can put alum in a silty bucket of water and it will clear up in minutes..
I know a guy sprayed wd40 on his wrists for his arthritis.

Wow, I need try that one next time..

For reals on the alum though..
https://en.wikipedia.org/wiki/Alum

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Offline Homer67

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Re: Your opinions: Best filtration systems
« Reply #18 on: September 29, 2013, 01:17:07 PM »
Ditto on the Katadyn Pro.  I just do not want to ingest what is in the tablets.
Ah Big Bend, we will soon return to reacquaint ourselves in our ritual of blood, exhaustion and dehydration. How can we resist the temptation to strip ourselves of the maladies of civilization?

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Offline dougstar

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Re: Your opinions: Best filtration systems
« Reply #19 on: September 30, 2013, 11:58:24 AM »
Katadyn Pro for me. 

5 trips so far with no problem and same filter.   
Just run bleach water thru it after the trip.

I always bring a few tablets just in case.

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Offline sleepy

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Re: Your opinions: Best filtration systems
« Reply #20 on: October 01, 2013, 07:24:38 AM »
An old-timer told me once that you can put alum in a silty bucket of water and it will clear up in minutes..
I know a guy sprayed wd40 on his wrists for his arthritis.

Wow, I need try that one next time..

For reals on the alum though..
https://en.wikipedia.org/wiki/Alum
Check it:
http://m.youtube.com/watch?v=G9BY69KnzoU&desktop_uri=%2Fwatch%3Fv%3DG9BY69KnzoU

It's never too late to be what you might have been-Geroge Elliot

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Offline Reece

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Re: Your opinions: Best filtration systems
« Reply #21 on: October 01, 2013, 09:23:05 AM »
Looks like I'll be taking some alum on my Marufo Vega hike! Anything I can precipitate (is that the right word) out of Rio Grande Water will be helpful.
I'm going to have to figure out how to scale down the system though.
I'm not carrying a 5 gallon bucket plus, I've got a gravity filter not a pump.
« Last Edit: October 01, 2013, 09:54:00 AM by Reece »

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Offline elhombre

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Re: Your opinions: Best filtration systems
« Reply #22 on: October 01, 2013, 10:01:14 AM »
"Just run bleach water thru it after the trip."

The filters are made to remove this kind of stuff out of water.  The carbon absorbs the inpurities like chlorine (bleach).  The best thing to do is take the filter out and completely dry it out before storing it.  This will greatly slow down the growth of stuff inside the small passsages throughout the filter. 

We use the katadyn filter as well.  Then we put the oxygen tablets in when we are done.  There was a post on 14ers.com about a guy who simply dropped his cap to his water bottle right next to the stream he was filtering from in CO.  He came down with a worm 2 weeks later and figured it came from that short contact with the ground.  I noticed this story because it reinforces my idea that the pills will kill anything that got by the filter.  Or, it will kill anything that ended up in my water container that didn't pass through the filter.  Such as the tubes co-mingling in the bag I store my water filter in when backpacking.

 
First Russian Collusion, then Obstruction, then illegal payment to Stormy Daniels, now no formal vote on impeachment for a 30 min. phone call to Ukraine

No evidence, just more secret investigations and Shifty lies perpetuating insane blinding anger

America will survive.  God Bless America

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Offline Cliff

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Re: Your opinions: Best filtration systems
« Reply #23 on: October 04, 2013, 06:47:40 PM »
Without getting into even more detail (than I already have), I included some of what I have distilled over many years of using/researching filter/purification methods.  Keep in mind, before posting anecdotal evidence from your experience with your preferred method of purification, I know more than a few old timers who drink straight from the river, and have never had any issues, not that I would ever do it, or recommend it.

In reality, many water sources available when hiking have a very low risk of causing any issues at all, and can be used safely with no treatment at all.  But, it's best to play it safe, especially if on an extended trip where getting sick could cause a dangerous situation.  In addition, no water treatment method is foolproof, and it's best, when possible, to plan out water usage so as to take advantage of the cleanest/purest sources, and not try to test the limits of your chosen purification method.

Chemical purification- The Sweetwater "drops" are nothing more than household bleach at a 10,000% markup, albeit in a nice bottle, but there are smaller dropper bottles available that are just as nice.  Also, the Sweetwater drops have usually been on the shelf, the store or your own, for months (years sometimes).  Bleach should always be bought fresh before use for water disinfection- check the date when buying it at the grocery store, also.

The two part chlorine dioxide drops/tabs (Aquamira, etc.) have a longer shelf life than chlorine bleach, but the same issues with cold temps (4 hour dwell time), particulate load, and some pathogens (like protozoans).  If used as the sole purifying method (bandanas don't really count as a pretreatment), looking into usage/dosage guidelines is prudent.  Same goes for household bleach.  The chlorine based methods are really better suited for use with clear water, or as as post filter (again, bandanas don't count) secondary treatment for viruses.

Pre-filters- A pre-filter will extend the like of any filter.  Sweetwater had a great pre-filter that could be opened for drying/replacing the media, but I don't think it's made anymore.  I know bandanas have been imbued with almost mythical powers by hikers, but, while a bandana is better than nothing, it really isn't enough to guarantee chemical/UV purifiers will work at regular doses, and won't do much to reduce the clogging of filters.

Gravity filters- The gravity based filters are problematic for on-demand supply, like refilling mid-hike.  They are better suited to once/day (overnight), large volume generation.  They are very slow, especially in a size suitable for hiking.  Some of the pump style filters can be rigged to act as overnight gravity filters, if desired.

Pump Filters- All hiking filters have similar micron ratings.  The important thing to look for in a filter is to make sure it's ceramic.  Though they are more fragile than paper/membrane elements, they are much easier to clean/dry/store.  The Katadyn mentioned earlier is ceramic, but the MSR ceramic filter, with it's much easier pumping action, usually gets higher ratings for ease of use.  I have one myself, and have had to hide it to prevent friends with the Katadyn from poaching my filter at camp.  The Sweetwater filter has/had the easiest pumping action, but the membrane-type filter is an absolute nightmare to properly store/care for- the guidelines at one point amounted to a 30 day lifespan after first use.  MSR bought the Sweetwater company.  It would be nice to see them combine the Sweetwater style pump with a ceramic filter.

Disposable/limited use filters- there are a few very small filters that can be placed on a water bottle, in-line with a bladder, or used like a straw.  These are great for saving weight or emergency use, but most are effectively "one time/trip use".

Settling- rafters/boaters, who were the early users of the alum method for camping, are abandoning alum, and opting for reusable "filter bags".  Alum can take too long to work with some sediments, and also affects the taste of the water.  It was primarily used for dishwashing water.  Drinking water was usually settled overnight without any additives, or gotten in bulk from clear sources- springs, side streams, etc.  Carrying 10 gals of water is not an issue in a raft/canoe.

Charcoal post-filters- The carbon filter add-ons/built-ins are pointless for hiking use.  They only real benefit they could provide would be to remove some chemical pollutants, but at the size used for hiking, the output would be too slow to be feasible, and the lifespan too short.  The hiking versions really aren't that good at removing odors/tastes, and are more likely to introduce odors/tastes unless carefully dried before storing, which is problematic.  I suppose if there were an area with a known water contaminant, like arsenic, selenium, etc., that could be eliminated by charcoal filtering, using a separate additional cartridge may make sense.  Although, packing in your own water is likely the recommended method in those cases.

UV- as mentioned by others, is only for use on very clear water, or as a secondary viral treatment on filtered water.

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Offline trtlrock

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Re: Your opinions: Best filtration systems
« Reply #24 on: October 04, 2013, 09:02:23 PM »
Lots of great information Cliff -- thanks for posting.
John & Tess

"...and I'll face each day with a smile, for the time that I've been given's such a little while..." - Arthur Lee

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Offline kevint

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Re: Your opinions: Best filtration systems
« Reply #25 on: October 11, 2013, 10:53:03 AM »
The two part chlorine dioxide drops/tabs (Aquamira, etc.) have a longer shelf life than chlorine bleach, but the same issues with cold temps (4 hour dwell time), particulate load, and some pathogens (like protozoans).  If used as the sole purifying method (bandanas don't really count as a pretreatment), looking into usage/dosage guidelines is prudent.  Same goes for household bleach.  The chlorine based methods are really better suited for use with clear water, or as as post filter (again, bandanas don't count) secondary treatment for viruses.

If these are your method of choice, it is worthwhile to call the manufacturer for additional detail.  I carry Micropur and a rolled up Platypus bottle with me when I travel to Africa for work in case I need to drink tap water as a backup to bottled water.  I buy a new pack annually and throw away the old tablets.  I also have it around as a last ditch backup during hurricane season and have very rarely used it in the outdoors.  When I was first researching water treatment options I chose it because it gets everything except chemicals.  I read some reports that the four hour wait time was unnecessary so I called the manufacturer's customer service department.  The lady told me that they have to advertise wait times under the most extreme scenarios and that I should wait the full four hours only if I had to break through the ice to draw muddy brown water from a mud puddle.  For pulling cool, fairly clear water from a stream, a wait as little as 15 minutes would be sufficient.  Call the manufacturer and get the information yourself--don't trust me on this--and do so at your own risk.  I usually wait 30 minutes to be safe.
 
Also, remember to keep the bottle out of the light while waiting for the treament to take effect.
-- Kevin (W5KLT)

"It's not an adventure until something goes wrong."  --Yvon Chouinard

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Offline Reece

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Re: Your opinions: Best filtration systems
« Reply #26 on: October 11, 2013, 12:05:11 PM »
I got my 1-micron polyester diesel fuel filter sock in the mail yesterday. I plan to cut it up and make coffee strainer size filters for river water silt. It will be a pre-filter instead of using alum.

http://briangreen.net/2011/06/ultralight-17g-1-micron-water-filter.html

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Offline Cliff

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Re: Your opinions: Best filtration systems
« Reply #27 on: October 14, 2013, 12:10:43 PM »
I got my 1-micron polyester diesel fuel filter sock in the mail yesterday. I plan to cut it up and make coffee strainer size filters for river water silt. It will be a pre-filter instead of using alum.

http://briangreen.net/2011/06/ultralight-17g-1-micron-water-filter.html
I would test that guys system under your expected conditions before relying on it.  He is obviously a "weight weenie", and those guys have a long history of bad ideas (and some good ones, also).  1 micron seems too fine for pre-filtering all but tap-clear water (clogging due to small total filter area).  1 micron is also too large for bugs, and would still need disinfection.  The best pore size for this type system is one that will remove particulates above the size that inhibits your chosen chemical purifier, or removes enough particulates to prevents your final filter from clogging excessively.

The biggest issue with his system is the funnel design.  Smooth supporting walls don't work for a "cone" style filter, that's why there are vertical ridges in coffee filter cones and baskets.  The smooth wall, combined with water surface tension, effectively prevent any flow other than at the tip, or wherever the cone isn't contacting the wall.

If you are planning to pull water from the Rio with his system, it would be very frustrating to use.  I can't remember the exact pore size used for Grand Canyon trips, but I think it's 3-4 microns, or even larger.  The most popular site for rafting bags is filterbag.com .  Much more info is available on the yahoo GC rafting group.

Keep in mind that surface area is the critical factor, because filters work by clogging.  Any weight weenie savings of a few grams gained by cutting it up will likely be paid for in frustration during use.  Especially in the desert where water needs can be very high.  There are also different filter bag materials available.  Some are lightweight and don't absorb water, and might be better suited for reducing weight, especially after use.

Also, being able to pour into a bucket shaped filter increases usability, since there are fewer accidental spillovers/arounds than most other methods.  There might be a hiking cooking pot sized filter bag that can be used how the rafting sized bags are in a 5 gal bucket-  Put the filter bag inside the bucket, fill, then lift and hold until the flow rate begins to irritate you.  Rinse, repeat.  The bag can be rinsed in the dirty water, then filled and lifted for a few seconds to purge the outside.  Follow with a true bug filter, or chemicals.

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Offline Reece

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Re: Your opinions: Best filtration systems
« Reply #28 on: October 14, 2013, 12:25:24 PM »
Ok...but I'm going to try it anyway. Tap water runs through it way faster than a standard paper coffee filter. Maybe I'll be rinsing a lot. I hope to find a pool out of the main current where the silt has settled some - maybe even dig my own hole to dip from.

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Offline Cliff

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Re: Your opinions: Best filtration systems
« Reply #29 on: October 14, 2013, 03:50:03 PM »
Ok...but I'm going to try it anyway. Tap water runs through it way faster than a standard paper coffee filter. Maybe I'll be rinsing a lot. I hope to find a pool out of the main current where the silt has settled some - maybe even dig my own hole to dip from.
Tap water running through it fast is no indication of how water with particulates will run through.  With clean water, the water that has passed through the filter can exert enough force to pull more water through, negating the lack of ridges/channels.  Also, the water is able to flow vertically within the filter itself fairly easily.

Part of what makes his system even remotely work with the smooth wall cone is the mesh/matrix nature of the filter bag material.  It provides the channels necessary to allow the liquid to flow at the cone-filter interface.  This effect disappears as soon as the flow through the filter slows due to clogging.

Once the flow is reduced due to a layer of particulate on the inner surface, the external water doesn't exert enough force to pull more water through, and just sits there.  In doing so it increases the backpressure on the water trying is to come through due to gravity.

This is fairly easy to test out with coffee filters when making coffee.  If you try to line one of the "permanent" metal or cloth filters with a paper filter, the flow goes to a trickle.  Lift it and put it in the ridged holder, and it starts flowing.

The filter bag should be pretty sturdy, and reusable.  It shouldn't hurt anything to mix up some yard dirt in some water, and see how much silty water the bag can the filter before before clogging.  Can't be any worse than running some Rio through it.  Might be nice to know before cutting it into pieces.

 


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