Most efficient gravity filter system – need market update

[Yoyo]

OK, so I'm back to square one. Last year, I devised my own gravity filter system using a Platy 3-liter hydration reservoir, some Platy tubing, the Frontier Pro, and some tablets (Jason Klass' system is pretty much the same). The downsides to the system were as follows:

1) The wait time for the tablets to work prior to the filtration was really annoying. (Remember, the Frontier Pro only filters protozoa, not bacteria. Need the chemicals to kill the baddies).

2) The limited volume of my 3 liter Platy hydration reservoir aggravated problem #1, meaning I would have to run more than one batch when hiking with a partner, doubling the wait time. Furthermore, the small opening of the Platy reservoirs means they are a pain to fill. (Yeah, you can use a cut off water bottle, but it is still somewhat inconvenient).

3) Worst of all, the system was rather slow. The Frontier Pro filter (probably due to the carbon element) took forever to filter.

As a result of these problems during intially testing on an overnight trip, I ditched the whole system and decided to go with my trusty Sweetwater filter, which weighs in around a hefty 11 or 12 oz. I found that the quickness and ease with which I could filter from the ever present streams in the Colorado Rockies made up for the extra weight. I found that the weight was compensated by the less water I was carrying between refill points.

My conclusion: A fast and convenient pump filter system, while heavier, works better in an environment where water is plentiful and you are resupplying perhaps every couple miles. If you're hiking in a desert environment where refilling is sporadic, then yes a gravity filter, albeit slow, is your best bet. (However, after a trip in Big Bend over the winter in which I had lug gallons of water, I have sworn to eschew desert hiking altogether).

Now I'm back to square one. I am still trying to find a way to ditch my heavy pump filter. Yesterday, I finally got a chance to inspect the Platypus Clean Stream system at REI up close. I like the fact that the dirty bag has a 4L capacity and a shut-off valve. Huge plus. I like the fact that it filters 4L in 2.5 minutes (per the advertising). I dislike the fact that the filter cartridge is unnecessarily heavy and that the system includes extraneous items (i.e., the "clean" bag).

The Sawyer inline filter caught my eye at REI as well. At 1.8 oz, it seems like a winner. It also filters out 99.999% of all baddies (except viruses) just like the Clean Stream does. I am now thinking about buying the CleanStream "dirty" bag and hooking it up to the Sawyer.

What do you guys think? Will the Sawyer produce water that is just as fresh tasting as the Clean Stream? They both appear to utilize the same hollow fiber technology.

Ben Tang, are you still around? Tony?

Thanks guys for reading this long post.

[Roleigh Martin]

David, my mind / research has come to the same conclusion. I bought the AGG Gravity Filter system and was horrified over the slowness of the Aqua Mira Frontier Pro filter (day 1 was fine, days 2 on the trail took about one hour per liter to filter, even with brand new pre-filters). I just got the 1.8 oz Sawyer inline filter and wonder if I can salvage the other parts of the AGG Gravity Filter system to use the replacement Sawyer inline filter.

[Troy Ammons]

MSR sweetwater drops have a 5 minute wait.

You can get 1 micron polyester bag filters, cut them up and make a cone filter to filter out the bugs. Its not a gravity filter per say, but the water runs right through.

I think the aqua mira is better used as an emergency backup.

[CW]

I use the ULA Amigo system. It's not the lighest possible gravity solution but it's lighter than a quality pump filter and about as fast without the effort.

[Walter Carrington]

I got this Sawyer water bottle/filter at Walmart:
https://docforgey2.com/more.asp?pid=50
except, no faucett adapter with the Walmart bottle (and $2 more). If shipping is not too expensive then the docforgey2.com is better. $39.99 there. Also, $34.99 for the inline filter there.

The water bottle filter uses a top that fits the standard Nalgene wide mouth water bottle, so this Nalgene bottle (96 oz capacity, 2.6 oz weight) with the Sawyer water bottle top and a bit of tubing and you've got a gravity fed system. I'll either do that or make something out of silnylon.

Does anybody know what material water tubing is made out of?
usplastics.com has too many choices.

[Brad Groves]

David,
I'm new to the gravity system… but after reading up here, I bought the Sawyer inline filter. I'm currently using it with a little tubing and a 5L bladder from a box of wine. The valve assembly/tube junction needs some serious help, but it works for now. (I've just been jamming the tube into the spout; get a little spill over and the connection is a little tenuous, but hey, one step at a time.) So far so good. There is still a certain simplicity to a pump filter; last trip we had some pretty funky water near shore, so took a canoe out to deeper and cleaner water. Would have been a pain for my current gravity system. If I worked out a better junction it would probably be all right. I do need to work out a more efficient way to fill if I keep going that way, though. I'm thinking it might be easier to use an open-topped water bag with the Sawyer…

[Tony Wong]

David,

I am still alive and I have updated my detailed review of the Sawyer in line filter.

I have also added photos to the review to better show how I use it.

For myself, I use the new Platypus 4 L Water tank that has been redesigned…a little heavier than the old one, but it is sooo much easier to seal up nice and tight.

I used the 4 L water tank on a day hike for 22 miles inside my pack fully loaded and the zip lock type closure held nice and tight.

For me, the key using the Sawyer filter with things that I would already have….I always carry my 4 L water tank for dirty water for in camp and I use my 1.8 L Platypus Hoser Hydration System as the catch bag for my filtered water vs. carrying another Platypus bag for clean water.

I have down graded my review of the Sawyer from 4.0 to 3.5 due to two things that were pointed out by another reviewer: 1. You have no way to test the filter to see if it is working or not working. Matter of faith or you get sick. 2. Reports are that in muddy or water that is not clear, the filter may clog up. I have not had any experience wtih this as the water in the Sierras is crystal clear in most cases.

The only other knock against the Sawyer is that there is no carbon in the system, so the filter is not going to improve the taste of the water.

The Frontier Pro never made sense to me because you had to use chemicals with it, where I don't with the Sawyer.

I highly recommend taking a plastic pint bottle, disposable water bottle type that weights 0.5 to 1 ounce for use on the trail with the sawyer filter.

Much more convient and fast way to get a drink of water on the trail without pulling out the whole gravity filter system.

Hope that this helps.

P.S. Based on what I am seeing….Sawyer and the Platypus Clean Stream are using the same hollow fiber technology.

-Tony

[George Phoenix]

Last time I was out, I too was annoyed by the slow speed. My solution was to sit on the Platy forcing the water through the filter at a much faster rate. It worked great.

[Michael Davis]

In clear mountain streams, I use a Steripen Adventurer and in Florida swamps, I use the ULA Amigo gravity bag with the Sawyer PURIFIER (removes viruses) into a soft sided Nalgene.

As to the taste and odor problem, my solution was to sew a small bag about 2" long by 1" in diameter and fill it with 1 ounce of aquarium charcoal. Then sew the end closed.

With the gravity system I simply keep it in the Nalgene with the clean water. When using the Steripen system, I put a charcoal bag in the dirty water before it is treated, shake it around and remove it, then treat the water.

Works great and is simple.

[Harlan Bruce]

I bought the Platy version. It lasted three liters and would not backwash. A waste of money. I'm going to try out a Frontier Pro + Cl tabs on my next trip. The ultimate filter is my MSR ceramic cartridge. Forget the name, but it will filter pondwater with no trouble. You may have to clean it often with really dirty water, but it is easily done in the field. I will always hump this thing – all 16 oz or so of it – to areas where the water is bad/stagnant such as Mesa Anguilla in Big Bend. And it improves the taste of the water out of the tap at home.

[Huzefa @ Blue Bolt Gear]

>2micron mesh pre filter cap to remove silt
>Aquastar mUV

For pre filter cap you need:
Platypus filter link
2micron mesh swatch which you bond on the inside of filter link.

Idea is that you fill up your large platy with water and screw on the filter cap. Then sit on it to force the water through.

Collect the water in your clean platy/bowl/pot/mug. It will be free on silt and you can purify it with mUV.

It doesnt improve color/taste but that is a small compromise.

[Richard Mueller]

Michael,that is an interesting use of the charcoal. When using your Steripen system, your charcoal bag works effectively by just placing it in the dirty water in the nalgene and shaking it around a minute and then removing it? I'm thinking I suppose so because if one uses a pump filter or gravity feed filter with charcoal the water passes through the charcoal only for a second or so.

Another possible option for a lightweight thorough filtering system could be using the Katadyn Bottle Adapter with Activated Carbon ( 2.08 oz ) with a steripen ( or Aquastar) UV water purifier. I have no experience with the flow rate of the Katadyn Bottle Adapter with Activated Carbon though I'm guessing it's as fast as the diameter of the tube coming out of it. Before using the Katadyn charcoal product though, I suppose one would want to use some kind of prefilter such as a bandana, coffee filter, or the Steripen Prefilter or FitsAllFilter. That's like using 3 steps or stages to purify your water.

Presently, I use the First Need Deluxe Purifier. I know it's a bit on the heavy side, 16-20 oz, but it does everything I'm looking for in a water filtering/purifying system ( it's thorough ) in one step or stage and it works well. I like the idea that I can pump the water and drink it right away. No wait times or any other messing around. However, a lighter system would be nice. The Steripen with some kind of use of charcoal such as your charcoal bag or the Katadyn Bottle Adapter with Activated Charcoal, albeit with prefiltering as well, may produce the same filtering/purifying results as the First Need Deluxe Purifier.

[Dan Cunningham]

A couple of weeks ago I finally got the Frontier Pro gravity filter I made out on the Superior Hiking Trail. Having read reports that the FP can clog quickly on the clear (but full of tannins) waters of northern MN, I also brought my Hiker pump as a backup. The FP filtered the first couple of gallons like a champ, and then quickly slowed down. I gave up on the second day.

It really depends on your hiking style and where you are going. I've decided that the pump works better for where I tend to go. My method was to filter 1.8L to my Platty and immediately drink it down to 1L, then hike. When I ran out of water, I just repeated the routine at the next water source – never carrying more than 1L. The pump was fast and tasted great, and it weighs 1/2 as much as the .8L that I drank before I started hiking after each water source.

After my hike, I decided I'm just sticking to my hiker filter. It may add to my base weight, but being able to carry just 1L, quickly filter more water, and keep on moving actually ends up being lighter, faster, and more reliable for me overall.

[Jim MacDiarmid]

Hmmm. . . does anyone know about the water quality in New York? I just started using the Frontier Pro + bleach as a fill and go system, and I love it. I have no problems with clogging in the Sierra. But now reading about the Minnesotans' issues, I wonder if I'll have the same problems when I relocate the NYC, hiking in the Catskills, etc. I didn't get rid of my Hiker Pro, but man, it'll be hard to add 8oz back on to my base weight.

[EndoftheTrail]

David:

Greetings from Krakow, Poland. It's evening now, and I am absolutely the ONLY soul here in this small hotel. Being that there are no other guests either present or forthcoming, the owner himself took off for the night — although he was kind enough to leave the reception area unlocked so I could use his computer. Kind of weird (and nice) to have the entire hotel to myself… but anyway…

As you know, I too have tried the Sawyer purifier (I liked the idea of using no chemicals). Alas, the Sawyer purifier didn't fit my needs for two reasons — the second one being a 'show stopper':

1. As Tony mentioned above, the Sawyer will not improve water taste. This may or may not be a factor for you — depending on whether your water sources are 'funky' or not.

2. The Sawyer requires a good priming from a water tap every time it dries out. In practice, this means priming prior to each trip. Once primed, the core likely won't dry out during the course of a trip but another priming will be required when stored in-between trips. I didn't like the idea of starting each trip with a semi-dripping wet filter — but the time I failed to prime — I got e-x-c-r-u-t-i-a-t-i-n-g-l-y s-l-o-w performance!

Given what you wrote, I don't think you will be happy with the Sawyer either…

[Tony Wong]

Just a add a little information to Ben's good observations: The Sawyer inline filter does not need to be carried "wet"/primed.

I simply prime the filter by sucking on the output end of the filter to start the process.

Now, I have read that the Purifier version of the Sawyer filter that removes virus need to be primed and that you can not do that in the field easily.

The only way that I could think of is to sit on the dirty water bag to create enough pressure to prime the system.

Just a guess and I have only been using the filter and not the purifier.

P.S. Ben, great to hear from you and safe journeys. You going to post up some pictures of your world wide adventure???

-Tony

[Rick Cheehy]

Ben, I'm so jealous, have a wodka and some papikash for me bro! Is it safe to sit on the platy and force the water through? This seem like a pretty good solution.

[EndoftheTrail]

Oops, my bad! My description about priming relates only to the Sawyer purifier. I have no direct experience with the Sawyer filter. I misread David's post, thinking he was talking about the purifier.

And thanks, guys, for your well wishes. No pics yet, but I may just bore you guys with a long TR at the end of my trip (in late November). I will do my best to stay well and stay safe. :)

[Michael Fogarty]

I've used ULA gravity systems off and on from when they were first on the market.

I liked the original the best, but found that I always get water while hiking,and the Katadyn Hiker is a faster and easier way to water up for me, anyway.

It took quite a few trips of watching others pump and be finished, then stand around waiting for me, to realize that a pump filter is the best way to go for me.

I've used Aqua Mira too, which I like, but still think a pump filter is best overall way to go.

[Yoyo]

Thanks all for your replies. Tony, I re-read your review on the Sawyer gravity set-up, but didn't seem to find a definitive flow rate for the filter. Is it like around 1 L / min, or much worse? Also, what is the taste like? I hike mostly in the Colorado Rockies at 8000' or above, so the water is generally pretty clear.

The flow rate for the AquaMira Frontier Pro is just unacceptable for me, plus the fact that you have to wait for chemicals to cook.

I would like to hear more reviews of the Platy Clean Stream. I noticed one of you said it clogged quickly, but was that perhaps an early production model? Maybe it's been improved since then?

[Tony Wong]

David,

Humm….to be honest, I have never timed the flow rate.

I can tell you that when I use the filter with the pint bottle, I can "suck" water through the filter about half as fast as I would if I was using a straw.

Essentially, I have not felt like I was delayed in getting water on the trail using the method above.

Using it as a gravity filter, I think that I have been able to fill up my 1.8 L Platypus Hoser in 2 or 3 minutes?

To be honest, since I have used it as a gravity filter in camp, I have been running around doing other things while the filter has been doing its thing….so speed was not too important to me.

Speed of the gravity filter is going to be determined by the clarity of the water (is there a lot of particles/dirts/debris in the water that you are filtering) and the length of tubing that is used between the dirty water bag and the tubing from the filter to the clean bag.

I don't know the scientific reasons for this, but the longer the tube the more suction might be created which speeds up the rate of flow…so this is a variable in the speed or rate of flow.

I agree, if someone is testing the Clean Stream, you would have a predictable rate of flow because the system is uniform.

Making your own gravity filter creates a variable in tubing length = increase or decrease of rate of flow from a known standard, such as the Clean Stream system.

Anyway, another way to speed things up….sit on the dirty water bag, which increases pressure and speeds up the process.

I am so lazy now that I just lay my dirty water bag on a fallen tree or rock and let gravity do its thing….as long as my clean bag and filter are pointing down hill, gravity works.

Okay, as for the taste, the Sawyer filter does absolutely nothing to improve the taste of the water.

There is no active charcoal in it.

If the water taste like crap to start out with then it is going to taste like crap on the way out…you just don't have to worry about bacteria making you sick.

-Tony

P.S. If I get a chance tonight, I will take some photos of the inside of the Sawyer filter to show people what is in there. Photos would be posted to my reader review. The new ones are glued shut. Sawyer was saying that people were opening them up and poking around inside and damaging the filtering tubes.

[Ross Bleakney]

I use the sip-and-go method when hiking and a drip system when in camp. The drip system is similar to yours (one clean platypus, one dirty one). I don't treat before filtering. I used to use a Seychelle, but recently ordered a Sawyer. The Sawyer is noticeably slower. I may go back to the Seychelle.

In general, though, the approach is as fast as pumping (if not faster, since you have to deal with fewer hoses) and very light (since you carry no water if you are in a place with lots of water).

[Yoyo]

Ross,

Do you have any quantitative results comparing the Seychelle vs. the Sawyer? How do they compare in terms of technology (i.e., how good are they in terms of filtering out baddies)?

Tony,

Yeah, I'd like to see some pics and also some more testing results on the filter rate.

All,

I think I'm just gonna have to buy the dang Sawyer and Platy Clean Stream system and do some testing on my own.

David

[Tony Wong]

David,

I just uploaded a series of photos showing the dis assembly of the filter to show what the inside of the filter looks like and a few observations about what might make some difference between the rate of flow between Sawyer Filters.

Photos are in the User Review Section for Water Filters, Sawyer In Line Filter:

http://www.backpackinglight.com/cgi-bin/backpackinglight/reviews/display_reviews?forum_thread_id=5536&cat=Hydration%20-%20Water%20Treatment&cid=55

-Tony

[Yoyo]

Tony

Thanks for the pics.

I am curious how Sawyer substantiates their 1 million gallon guarantee. How can they be sure that contaminants are being trapped during those million gallons?

Also, can/must the filter be backflushed in the field to maintain cleanliness? I read somewhere that the Sawyer FILTER (0.2 micron?) can and should be backflushed, while the Sawyer PURIFIER (0.01 micron?) must be backflushed under high pressure, such as your faucet at home.

The Platy Clean Stream system uses backflushing to maintain cleanliness. Since both the Sawyer and Platy seem to utilize the same hollow-fiber technology, you would think that both would operate the same way.

Finally, why do I keep hearing that the Platy Clean Stream filter keeps clogging? Were these early production samples, or has Platy improved? Need to hear more feedback on this.

Thanks.

[Author]

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