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Heavier, Better Gravity Filter for the Lazy Backpacker
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Mar 31, 2009 at 10:52 am #1490072
the sawyer or the first need needs priming? hmm… I don't mind the chemicals, but i've been tossing around the idea of a gravity feed system for awhile since the girlfriend would prefer a filter of some sort… I like the idea of the .02 micron filtration at 3oz for the filter element, but if I have to prime it?… or just get water in the filter element before leaving on a trip? I didn't see a mention of that in the information section for the .02 micron filter or gravity feed setup.
Mar 31, 2009 at 1:04 pm #1490106We've got a sawyer sp120 hooked up to a ULA Amigo and all we have to do to prime is fill the bag with water and suck on the hose. We used it on 3 trips last summer and never had any trouble.
Mar 31, 2009 at 1:22 pm #1490115David:
I have no experience with the 120, but it is a different animal — a filter — and not a purifier.
As mentioned, when I tested out the Sawyer purifier at home — after priming with the supplied rubber cup attached to my kitchen faucet — water flow was quite good. But out in the field — because I had failed to prime prior to my trip — the output was absolutely miserable.
After my trip, when talking to Sawyer customer service, the lady was emphatic that the purifier must be primed with a faucet every time it dries up (i.e. when stored between use). When asked, she even said the unit will NOT prime properly by sucking or manually pushing through a bladder of water. It needed the force of a faucet, so she said.
I didn't much like the idea of starting every trip with a wet filter/purifier — so I quickly sold mine. I did not, however, try to disprove the Sawyer lady by sucking on the purifier. Maybe a current owner of a Sawyer 125 purifier can give that a try and report back?
Mar 31, 2009 at 5:19 pm #1490176Today I made one of these using an AGG 1 gallon water bag, two hardware store plastic hose fittings, some tubing, and a Frontier Pro filter. I stripped the frontier of the plastic lid, the rubber outside, and the bite valve – this removed over 25% of it's weight (.6 oz).
I have 30" of hose from the bag to the filter, then I remove my bite valve from my 1.8L hoser and hook the hydration hose to the filter. This makes a rather long hose length of over 6' total (with the filter in the middle). The longer hose helps keep the flow rate of the Frontier Pro up.
Filter = 1.4 oz
Attachments = 0.5 oz
30" Rubber Hose = 1 oz
AGG Bag = 0.6 ozTotal = 3.5 oz
Tested flow Rate = .6L / min
Water will be pre-treated with tablets. One question, can you filter water before the 15 minute period is up, or does the charcoal and such work against the tablets?
Apr 1, 2009 at 9:01 am #1490367I visited the sawyer web site and located their manuals. The manual for the 0.1 micron filter does not mention priming. The manual for the 0.02 micron filter says priming is required.
I've taken my 0.1 into the field dry and it worked ok. It appeared to be slow, but since I was doing other things while it filtered, I didn't care.
In any event, it didn't take more than a few minutes to fill my 3 liter hydration bladder.
Apr 1, 2009 at 10:15 am #1490402I use the Sawyer purifier (0.02 micron virus removal) and it definitely needs to be primed at home by hooking it up to a faucet before every trip.
My ULA amigo gravity bag plus the Sawyer purifier, primed and full of water weigh a total of 14.9 oz. I know … that's heavy so you gotta like pure water to carry it but it does work great for stagnant swamp water in Florida.
For the taste removal component, I made a small bag from noseeum netting and put 1 oz of aquarium charcoal in it. I keep this in my water bottle.
Apr 1, 2009 at 4:27 pm #1490520Aaron, I really don't remember the flow rates. I never worried about it much because I would just hang it on a branch and go about my business. I know it wasn't fast, in fact it was probably slow, but even if it took a while, I wasn't bothered because I would use it for my future water needs and would finish up my existing water while I was waiting (cooking, etc.)
If you use the stuff sack that came with the kit for a gravity bag (it is designed with a hole for this and even has the fittings for it)and need to "prime" it, I just grab the bag and close the top (like a plastic bag) and put a little pressure on the bag to increase the flow. This seemed to work for me, YMMV.
I haven't use this for about 5 years so its been a while.
I now keep it in my 72 hour kit for emergencies. After this thread I tried it out again with the pump. I had water coming out the sides of the pump when I would pump it. I guess the "O" rings need replacing or some lubrication. After 15 years the innards might need a little maintenance.Apr 1, 2009 at 5:18 pm #1490532I emailed Aquamira with the question I had asked above – can I plop in the tablets wait for them to dissolve, then start filtering immediately to my platty with the filter in gravity mode?
They say: "We actually recommend this method you just described. The filter will not deactivate the CLO2."
This should mean only 5 minutes at the water source to fill my 1.8L bladder if you include setup and take down, and then keep on trucking and start drinking 10 minutes down the trail without the added resistance of pulling through the Frontier (which I didn't care for in my testing).
Apr 1, 2009 at 5:39 pm #1490541Dan:
The great selling point for CLO2 tablets is that they can treat protozoa (long treatment time notwithstanding) — something bleach and iodine can't match.
But if you're using the FP filter to block protozoa, clarify water and improve taste — and thus relying on the CLO2 tablets to kill viruses and bacteria only — then why not save the $13 and just use household bleach — which costs around 99 cents for a whole gallon at discount stores (you only need 6 drops per quart)? CDC, Red Cross, etc. all advise using bleach to treat suspect water.
I am assuming that if the 3-micron filter blocks the taste of CLO2 but doesn't hinder the effectiveness of the chemicals themselves, then most likely it does the same with chlorine
Apr 1, 2009 at 5:45 pm #1490545Ben,
Thanks for the tip – I'm going to think about that one…
For a pre-filter in my water bag, I snatched one from my Katadyn Hiker, which is 130 microns. It fit in pretty easy, and only weighs 0.125 ounces:
May 11, 2009 at 8:00 pm #1500651Chris Chastian wrote:
> Aquamira: 2.2oz rated at 190 litersBeing a newbie, does this mean you need to buy a new one after this amount?
May 11, 2009 at 8:33 pm #1500663Michael – Yes.
May 12, 2009 at 6:57 am #1500735Is it simply because the charcoal has lost it's effectiveness or that it can no longer be backflushed effectively to get a decent flow?
May 12, 2009 at 4:05 pm #1500870Both are valid reasons, but I expect that the decreasing flow rate will entice you to ditch it before the listed lifespan is reached.
Feb 10, 2011 at 3:22 pm #1695097Hey all, thought I'd share my new sawyer zero two setup with you, it works awesome. I put it inline with the Geigerrig Hydration Engine (bomb proof pressurized bladder) now the geigerrig does all the work that gravity would do and you dont have to suck, unless you want to.
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