ultralight water prefilter

I use the smallest cone shaped coffee filter available (#1 I think) in a small funnel for prefiltering. Then I dispose it in my trash bag. I don't want to risk re-using it after bacteria have a chance to grow on both sides of it when stored wet.

Never had a problem with this filtration method.

I dispose of my 1 micron pre-filter at the end of each hike I've used it on. I do wash it with water (kind of a back-flush) while on the trail, and have it dry out daily if it is not raining. When you buy them in bulk (I buy 6-12 at a time), it's cheap but not as cheap as coffee filters, but then 1 micron has it's advantages.

"About $3"

Plus $9.95 shipping. :(

looks like there are some on ebay for $3-4 and only a couple bucks shipping. search for 1 micron filter bag.

…

Pricing and shipping. Yes qty 1 from DudaDiesel is not cheapest way to go, but qty 5+ gets them for $2.50 apiece, so you end up saving money from DudaDiesel vs. buying them from Ebay at a certain level of qty. It's a math issue to work out for your needs. I used to use Ebay to buy them until I figured out the best way to get them.

Ps, Mike, thanks for the credit line. I'm glad I turned a lot of backpackers onto this fine pre-filter.

Well, here's my attempt at this thing:

As long as the screen is glued in there good I should be good to go. Just for everyone's info I used the Loctite Plastics Bonding System (an activator and super glue).

I'm kinda embarrassed to reveal my pre-filter concept before I found this post, but it's pretty darn funny so check it out:

This thing is a Keurig K-cup reusable coffee filter with a bottle top glued to it. The platy cap was going to be glued to the bottle cap, and that would allow for it to be threaded onto a platy container. This also would allow for easy cleaning as I could unthread the bottle cap to clean it out. I didn't totally finish it as I used the platy cap to make the other pre-filter, but intial weight measurements put this thing at about 0.7 oz…yikes. So anyway, I hope you had a good laugh at my expense, and I really appreciate this thread…only wish I'd a found it a hair sooner…of course if that had happened we wouldn't be blessed with the awesome apparatus above…ha ha ha.

Hi Mike and Roleigh,

I saw the 1 micron bio-diesel filter fabric bags that you guys are using as a pre-filter in your water treatment systems. I thought that was a great idea, so I ordered a few to try out.

I cut one down a bit, basically took off the top half, leaving the bottom section intact (it looks like a small upside down beanie) and took it on a day hike this last weekend. I attempted to treat some muddy snow runoff at one point in the hike, so I ran it through the 1-micron pre-filter and it still came out really turbid. Not much clearer than the water in the creek actually. I dumped it and ended up just collecting clean snow, letting it melt and then zapping the melted snow water with the steripen instead.

So, I'm curious as to how well these pre-filters have worked for you guys at removing silt from muddy water. I'm wondering if the problem is that water is passing through the seam of the filter bag where it was sewn together and so it's not really getting filtered through the 1-micron fabric? Maybe I need to cut out a section in a different way to avoid the seam and have a solid piece of the filter fabric instead. Any thoughts?

Thanks,

Nick

Couple of questions and comments, Nick. I only cut out the metal ring of the filter. Left the rest there. Did any water pour over the top of your cut-down filter?

Anyway, with murky water, the purpose of the prefilter for me is to get the dirty water that is going to be filtered by my .1 micron Sawyer filter – http://www.sawyer.com/SP122.htm to be prefiltered so that the Sawyer filter does not get immensely clogged up fast. The water that comes out of the Sawyer filter is then given a tablet of Chlorine Dioxide to deal with viruses, 20 minutes later, I can drink the water. With Beaver Bond, Silty water from Superior Hiking Trail, the water is still colored rusty color, but it tastes just fine.

Another SHT hiker, a married couple, they prefiltered their water with the same DuoDiesel filter (not my DuoDiesel filter, they had their own), then they used a Steripen to purify that water, and they drank that and had no complaints. I felt the water I drank was cleaner having been filtered down to .1 micron.

What were you doing with the water afterwards. After all, the word "pre-" in "pre-filter" presumes something is going to be filtering the water ultimately.

Thanks Roleigh,

I was careful to regulate the "flow" of water through the pre-filter so that water didn't make it into the container without passing through the pre-filter first (I poured water into my 1L Nalgene cantene from a water scoop with the pre-filter set in the cantene opening).

In this case, I was using the pre-filter with a steripen. The water probably would have been fine to drink after zapping with the UV light… I guess I was just expecting the 1-micron pore size to be fine enough to remove most of the sediment from the water. Instead the turbid water passed through the pre-filter and still came out looking turbid.

Roleigh, how much water could be filtered through the above filter bag before it needed changing? of course it depends on water quality, but any approximate numbers? thanks!

I have used a #1 coffee paper filter & soft plastic funnel for years.

going through this thread had me wonder (nobody posted anything about this) about the aquamira pro filter which only has a 3 micron granularity… it looks like for some of us (i am going to use the tablet method coupled with the frontier pro filter) this would be enough… but some here are going as low as .01 microns and that's after using a 1 micron pre filter and tablets… may i ask why?

can i replace my 3 micron frontier pro with the 1 micron diesel pre filter after using tablets? i mean, this route might be cheaper and better…

"can i replace my 3 micron frontier pro with the 1 micron diesel pre filter after using tablets?"

Haven't tried it myself, but if the diesel pre filter truly blocks all baddies bigger than 1 micron, then I don't see why it couldn't replace the 3-micron Frontier Pro.

Not a show stopper or anything, but in lieu of waiting 30 minutes and then drinking through the FP, it seems like you will have to carry extra bladder(s) — to treat dirty water and then to transfer treated water into clean bladder(s). Another thing, which may or may not be an issue for you, is the lack of a carbon / charcoal element to improve water taste.

Benjamin,

you are right! the fp would improve taste as well… forgot about that…

and i was thinking of treating my water first and then transfer it to clean containers (gravity filter setup with the fp filter)…

Benjamin,

another thing i could do would be to cut just a piece of the diesel 1 micron filter and attach it to the end of my tube that goes to the clean water, or just replace the prefilter on the fp with a piece of the 1 micron filter…

what do you think? or what would you do?

"Haven't tried it myself, but if the diesel pre filter truly blocks all baddies bigger than 1 micron, then I don't see why it couldn't replace the 3-micron Frontier Pro."

Benjamin, would it make any sense to try to insert a piece of the diesel pre filter into the front end of the Frontier Pro? Or, for that matter, to replace the entire Frontier Pro filter material inside the plastic case with this thing.

–B.G.–

I don't think it's necessary, because I treat with chemicals first — to kill / neutralize teeny tiny viruses, bacteria small and large, plus the very smallest of protozoa species. The 3.0 micron FP can then block the bigger (and harder to kill) protozoa species, block sediments, and improve water taste.

from most of your posts (benjamin) and other's i think i'll just use the fp and tablets and that should work… a lot of people here don't even filter their water or even treat it with chemicals…

very interesting thread though…

http://www.filterbag.com/PENG1P3P-p568.html

Looking for more feedback on these filter bags. I found the ones above with plastic instead of the metal rings.

Does anyone have more/better sources? Would I be better of buying ones with the metal ring and cutting them out, or is anyone using filter bags with the plastic rings?

Any feedback and user experience appreciated!

Wow, Brian, what a great resource. I saw your link page but this other filter, slightly more expensive is superior as it is an absolute rated 1 micron filter:

http://www.filterbag.com/NMO1P3P-p184.html

“1 Micron”

“Size 3 (4×7)”

Only down side is that if the price shown is per one filter, one has to buy 25 filters at $10.21. (I confirmed such is the case)

“Precisely woven to ensure accurate filtration (absolute rated bags), this monofilament mesh withstands temperatures up to 325 F.”

I’ve sent an email to them asking them to read this thread and comment on these two filters they sell. I’ll update the board with their response.

Please don’t rely on these as your sole means of water filtration. The ‘absolute micron’ rating is at only 99% capture.

From Filterbag’s website:
“Filter bags made out of monofilament mesh or micro-fiber are given absolute ratings. A filter bag with an absolute rating will capture 99% of its rated particles in a single pass.”

The EPA standard is 99.9999% for bacteria and 99.9% for cysts.

The EPA testing protocol dopes test water with 100,000,000 bacteria per liter (10^7/100mL):
Fewer than 100 bacteria are allowed to pass through a filter meeting the EPA standards. The Filterbag ‘filter’ could potentially let 1,000,000 bacterial through!

If you chose your water source carefully, you’re not likely to encounter those concentrations of bacteria (something like one gallon of raw sewage in 10,000 gallons of water), but I don’t thinks it’s worth the risk.

However, the Filterbag filter would make a great pre-filter.

Hope this helps.

Great informative post. Thanks! As I mentioned in my earlier posts, I use the pre-filter before using either the Steripen or Chlorine Dioxide Tablets. If using the Chlorine Dioxide tablets, it is to take care of Giardia and Crypto only as they’re >= 1 micron and to kill those suckers off with the tablets requires waiting about 2-4 hours, otherwise just to handle bacteria and viruses (what you were talking about was bacteria), the tablets only require 20 minutes. The Steripen doesn’t need the pre-filter except to take care of visual sediment or wolf parasite eggs (which are larger/harder than Crypto/Giardia).

I heard from Filterbag.com and he made many good points — the thread of my correspondence is here:

https://docs.google.com/open?id=0B7L_TrVYTWZRRlZVZjJZUk8wQU0
Link.

He provides links which are in that PDF linked to covering our correspondence.

did anyone ever end up finding a good source of absolute 1 micron filter bags? the minimum order of 25 is pretty steep, did anyone ever end up placing one?

if we can drum up enough support i'd be willing to place the order…

http://www.dudadiesel.com/choose_item.php?id=PTFEP3S

Polyester PTFE Coated Filter Bag, 0.5 Micron
• Size#3, with hanging strap
• 8" Length, 4" Diameter
• PTFE Coated to 0.5 Micron Rating

$Ea. Qty
$ 5.25 1+
$ 4.60 2+
$ 3.75 5+
$ 3.60 10+
$ 3.40 25+

If you use a vice-grip, you can clip off and remove the metal ring and the resulting filter is <= 1 oz. I used this on my JMT hike as my pre-filter. One lasted the whole hike.