Heavier, Better Gravity Filter for the Lazy Backpacker

There are serious viruses that even the 0.2 micron filter won't take out. The EPA recommended 2 drops of bleach per liter in your feeder bag will take care of the viruses and also retard growth of various flora in your filter. If you don't like the taste of chlorine, you can add yet another (charcoal) filter to your setup.

Thanks for posting the flow rate for the filter. I've been curious if the manufacturer's data were honest.

As far as I know, it's not possible to filter viruses with a commonly available consumer type filter.

Sawyer makes a 0.02 micron filter they claim will filter viruses. That's right, 0.02 micron not 0.2 micron.

It is fairly costly, (somewhere between $100 and $200) which is why I suggested you add the EPA recommended 2 drops of chlorine to your dirty water instead. It will kill the viruses so you don't need to use the expensive filter. You're platy filter will remove the things the chlorine doesn't kill effectively.

If you don't like the chlorine taste, you can get a cheap charcoal filter which you can install below your platy filter to remove the chlorine.

Check into the known contaminants in your hiking area. Viruses are not known as problems in many areas.

Problems come and go. Unless there is an ongoing monitoring program, there's no way of knowing what's in the water.

If you elect to take the risk of drinking untreated water, fine. If you don't, what I previously recommended will significantly reduce your risk of getting sick.

I was under the impression the Frontier Pro contains charcoal. Is it a fact that the platy one does not?

Also as stated already, neither seem to be a 'one product solution'

You are correct. The frontier pro contains charcoal, the platy does not. If the Pro had a smaller pored filter, it would be an excellent filter solution. Since it doesn't, I made up my filter from a Sawyer 0.1 micron filter followed by a Katadyn charcoal cartridge. Both purchased from REI.

Sawyer is guaranteeing their filter for life now by the way.

When I get home, I'll post a photo of my filter. It is very similar to the one that's the subject of this thread except of course, it has the additional charcoal filter.

Here's the promised photo of my filter setup. At 9.2 oz, it's a little heavy, but still quite a bit lighter than my miniworks which is a 0.2 micron filter with a charcoal after filter.

The setup shown uses a platypus 2 liter dirty water bag with a side exit that allows for heavier things like sediment to settle out. The black canister is the Sawyer 0.1 micron filter. The gray canister is a katadyn charcoal filter that removes chlorine and many other dissolved contaminants that get past mechanical filters.

I also installed a platypus inline valve after the charcoal filter and a fitting that lets me plug the filter directly into my nalgene hydration bladder.

This filter is slower than the miniworks, but I don't mind since I don't have to pump, I can tend to something else.

> Sawyer is guaranteeing their filter for life now by the way.

So what happens when it eventually clogs?
Do they replace it free??

1. So far as I know, you can backwash the filter to restore it.
2. I strongly suspect the in-line Sawyer filter is also "vulnerable" to the same risk of cold as the MSR Hyperflow…that is that the filter elements , if frozen, are permanently damaged and non-functional thereafter. Anyone have first-hand knowledge of this?

> > Sawyer is guaranteeing their filter for life now by the way.
> So what happens when it eventually clogs?
> Do they replace it free??

Maybe they declare that it has reached its end of life?

Cheers

The Sawyer filter, (and the platy, and most filters for that matter) will be damaged by freezing. Damage by freezing isn't covered by the warranty. I'd say if you're expecting cold temperatures, put your filter in a ziplock bag and carry it inside your jacket.

When the filter clogs, you backflush it.

These and other questions about the Sawyer filter are answered at http://www.sawyerproducts.com.

Ok, I found it.

BTW, I tried very hard to research these filters and this company (they are only a distributor, I forget the manufacturer, but I posted it somewhere on here I think) a couple of years ago and found almost nothing… hadn't looked lately.

Anyway, it appears that these are indeed lifetime filters.

Along with the normal assurances for manufacturing flaws, they guarantee them for life (which I guess means the life of the company?).

From the Sawyer web site:

"All of the Sawyer® water filters and purifiers come with a MILLION GALLON GUARANTEE!"

Back flushing must be very efficient in this design (which appears to be the same technology as the Clean Stream and other MSR stuff).

I'm ordering one to test. Thanks for the heads up, Herman. How difficult is the back flushing, and is full flow restored?

>How difficult is the back flushing, and is full flow >restored?

Chris,

Sawyer sells an attachment for back-flushing from a faucet. As far as I can tell, flow is completely restored. I've never back-flushed on the trail, but I've never heard about any difficulty. Also, the water sources on my hikes are pretty clear. When I used the MSR MiniWorks filter, the element only needed cleaning about once a year.

Which filter did you order? The 0.1 or the 0.01 micron filter.

H

> Which filter did you order? The 0.1 or the 0.01 micron filter.

The .1

Hello:

I have a very similar set up on my platy : no pre-filter.

the attachment that comes with the filter works wonderfully.

only complaint I have is that the filter needs to be "primed" (for lack of a better word) before it flows well. It's pretty hard to suck water into the filter unless you already have water in the filter. Once you get some water in there it flows really well. I keep my hose dangling, and sip whenever I'm thirsty.

the filter rides on my Blast's shoulder strap.

I've been looking over a bunch of different posts about gravity filters lately, trying to decide which one to buy or build.

I purchased a frontier pro and some chlorine tablets, thinking I was going to go that route and then I saw this thread and learned about the sawyer and platypus filters, both of which filter to a much smaller size than the frontier pro can. Then I saw the sawyer 0.02 micron filter which can even filter viruses.

So that got me thinking. I'd like to find the ideal balance (for me) between minimizing weight and maintaining a high standard of filtration. I've been using a first need purifier (made by general ecology) for years with exceptional results. My only complaint has always been that it's a bit heavier than i would like (at about 16 oz.).

But a few moments ago I had an epiphany. The first need purifier has a gravity feed option. You're supposed to feed the dirty water through the pump still but you might be able to circumvent the pump and install the purifier cartridge inline. You may have to prime it somehow to begin the flow of water.

I'm not sure if it will work or what challenges might arise but I think I'm going to go home and try it. I believe the cartridges by themselves weigh about 5-6 oz. which would put it in the same ballpark as some of these other gravity filters but with the added benefit of it still being a chemical-free purifier.

If it works, i'll post some photos showing the end result. Of course, if any of you have already tried this, perhaps you can save me the wasted time…

"I believe the cartridges by themselves weigh about 5-6 oz. which would put it in the same ballpark as some of these other gravity filters but with the added benefit of it still being a chemical-free purifier."

Don't we wish! The First Need purifier core weighs 10 oz. dry — and it's still fairly bulky. The First Need will do everything that a Sawyer can do — plus improve water taste because it incorporates a carbon core that the Sawyer lacks. But the First Need requires quite a bit more sucking effort!

Due to its bulk and the sucking effort required, I opted to stick with my chlorine/Frontier Pro combo. YMMV.

Nick, the First Need filter will work as a gravity system. If you read the instruction pamphlet it shows how, but they have it go throw the pump. First Need

I just omitted the pump and hung the system and it works great- I went through the whole Bowron Lake circuit (70 mile canoe trip) using it that way and had no problems. I also used it this way for 10 years when I had time in camp to hang a bag. Of course all of this was before my light weight days
There are lighter weight systems out there but none will filter/purify better.
I don’t use it any more because of the weight and high cost of new cartridges.

anyone know how much the sawyer .02 micron filter weighs without any of the adapters? the whole bucket kit, minus the bucket weighs 18oz according to the REI page for it…

I put together the first need gravity purifier by putting the purifier cartridge inline between two bladders/hoses. It worked fine but was a little slower than I thought it would be. You really had to "prime" the setup to get it to start pulling water through the cartridge and even then it seemed to be flowing at a rate of only about 1L/5 mins… maybe even slower. It would probably be fine, it was just slower than I expected and the priming work was more than I expected.

Ben, you might be right about the weight of the first need cartridges. I didn't weigh it, my 5-6 oz figure came off a website that sells the replacement cartridges. I haven't verified it one way or the other.

I sent an email to the folks at Sawyer asking them about the 0.02 micron purifier. They said the purifier cartridge should be able to be worked into a gravity system. They also said purifier cartridge itself weighs "a little over 3 oz." They don't sell the cartridges by themselves so the cheapest means to get it seems to be either the bucket system or an older product of theirs (SP135) which is a bottle purification kit (it looks like a drink bottle, the cartridge and some hose). i don't know if the bottle system is still available.

If you want a chemical-free purification system and don't mind spending a little bit more up front, this might be worth looking into.

Chris:

If you are absolutely sure that wherever you go, all your water sources will be free of viruses and bad taste — then indeed Clear Stream is all you need. No more fussing with chemicals.

OTOH, reading a few posts below… if you find yourself supplementing your Clear Stream with a few drops of chlorine — then the Frontier Pro makes much more sense than the Clear Stream! The smaller and lighter FP's built-in carbon element will remove all traces of chlorine (and other bad taste in the water as well) — something the Clear Stream can't do.

Tad, what kind of flow rate were you getting with that First Need gravity system?

I tried this several different ways with a barely used cartridge (Used for 3 days with clear water) and was unable to get a faster flow rate than 1L / 10mins timed with a stopwatch. I gave up and just decided to take the pump too.

Nick:

I've written about this before so this may be a repeat to you… but just in case it isn't…

I've tried the Sawyer before and it's too bad the unit — like the Clear Stream — lacks a carbon element to deal with potentially bad water taste. But the real show stopper for me is the Sawyer's need to be primed prior to use. Once primed, the Sawyer performs beautifully — but once the core is dry (say when stored in-between trips) — it needs to be primed again — using the rubber faucet attachment. Manual priming (squeezing water through from a bladder for example) doesn't quite work — not nearly as well as using the force of a kitchen or campground faucet.