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In line filter hydration
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L Lanian
(Lanian) - F

Locale: California, U.S.A.
In line filter hydration on 02/14/2014 21:45:36 MST Print View

This is actually a question for y'all.
I've seen several places/pictures where people have bought a hydration bladder, used a sawyer inline filter in the line, and drank straight from the filter.

I have a platypus gravity works 4L filter. Can I use the 'dirty' bag as a hydration bladder, and suck from the gravity works filter as an inline filter, attached to a bitevalve? Theoritically, would it be the same, or is the platypus filter setup differently that it doesn't work the same?

My reasons for this: I can carry 1.5L of water while hiking, then use the full 4L capacity at camp. The filter: I already own the platypus gravity filter, whereas I'd have to buy a sawyer filter.

Any tips/suggestions/experiences are helpful. Thanks

Adrien Baker
(AdrienBaker) - F

Locale: Kern County
Re: In line filter hydration on 02/15/2014 08:59:53 MST Print View

What you are proposing should work just fine. Some people will question the need for so much capacity--but if you already have something that works then go with it!


L Lanian
(Lanian) - F

Locale: California, U.S.A.
Reply on 02/15/2014 17:31:27 MST Print View

Thanks for the reply
The capacity may be high, but the weight is drastically low- the 4L dirty bag weighs less than a big zip hydration bladder.
82g without the hose
58g for the hydration kit/bite valve

130g vs the ~170g of a big zip

So I'm not sure the capacity hurts me here.
I'm more concerned with whether the dirty bag can handle being treated as a hydration bladder. It has a sturdy zip at the top, but sturdy enough to jiggle in a pack?

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: Reply on 02/15/2014 17:44:42 MST Print View

"It has a sturdy zip at the top, but sturdy enough to jiggle in a pack?"

I've been unexpectedly soaked when that sturdy zipper decided to open.


L Lanian
(Lanian) - F

Locale: California, U.S.A.
Bummer on 02/16/2014 01:23:15 MST Print View

Oh bummer. So you wouldn't recommend that, I take it. Was it at full/near full capacity? I was hoping only 1.5-2L would put less strain on it

Glenn S

Locale: Snowhere, MN
Re: In line filter hydration on 02/16/2014 02:14:36 MST Print View

The concept would work, but Bob's right. I wouldn't trust that zip all by itself. The 3L Platy has a bar that slides over the zip to secure it and is made for just what you're talking about. Sounds like dumping more money into it isn't your plan though. Maybe you could roll the top down a few times after it's zipped. There'd be lots of room left with only 1.5L in the bag. Maybe secure it from unrolling with a clip of some kind, or a wide strap that you could roll up with it and velcro the ends, like a drybag kind of closure. Just spitballing ideas I guess. Good Luck.

scree ride
flow rate on 02/16/2014 08:31:43 MST Print View

I tried the Sawyer inline with a hydration hose and really wasn't happy with it. The flow rate was too slow unless the water was forced through the filter. I used a pressurized bladder and it worked well, until the bladder started leaking.
If you want to filter while hiking, just let it run into a Fuji bottle. Get an extra cap, put a hole in one for the hose. I wouldn't bother with a bite valve.

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: Bummer on 02/16/2014 15:58:40 MST Print View

That water container is supposed to be filled up via the zipper opening, then closed, then carried by the strap handle.

If you change the game by putting it inside a backpack, then it might be getting squeezed from different directions, and that is what helps it blow the zipper.

It wouldn't be quite so bad if you filled it halfway, then squeezed the excess air out of it, then sealed it. Still... I don't know.

I mostly use smaller Platypus containers without any zippers.


L Lanian
(Lanian) - F

Locale: California, U.S.A.
Trial and Error on 02/23/2014 00:26:33 MST Print View

Well, I have a trip coming up in a few weeks. I'll give it a shot and let you know how it goes.
Trial and error gives the most definitive answers, right?

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: Trial and Error on 02/23/2014 00:34:18 MST Print View

"I'll give it a shot and let you know how it goes."

Those were the famous words of John Wilkes Booth.


Tony Ronco
(tr-browsing) - MLife
Re: Re: Trial and Error on 02/23/2014 13:16:34 MST Print View

"Experience is the best teacher, but a fool will learn from no other."

- Benjamin Franklin (from Poor Richard's Almanac)



The set-up you're thinking about, is rather similar to the one that I use:
Platy Gravity Works Clean Bag (4.0 Liter) as the dirty bag running through a Sawyer filter (= "no clean bag" utilized)

I've made some modifications to the Platy Bag itself to lighten-it-up/simplify-it ... and make it easier to set-up in gravity mode, but nothing to the zipper portion of the bag. In order the system to effectively work as a gravity filter, the set-up needs to establish a tall water column in order to have sufficient force to provide sufficient flow. (Tall water column = approximately 3' of tubing and the source bag hung high)

To date, I've yet to have that Platy Bag set-up leak from the zip top ... but never the less (as indirectly suggested in this thread) I always store it in an outside pocket of my pack just in case.
I no longer will have any hydration bag on the inside of my pack, as I've had a Camelback leak once when it was inside the pack ... a "very inconvenient" event marking the last time I'll ever store a hydration bag inside my pack :-(

EDIT: By the way, the Platy Filter that came with their Gravity Feed System was rated at a 50 gallon life capacity ... With just me using it (and religiously backflushing it each use) - there was no noticeable decrease in flow from MY use ... but it's use on Scout trips and by the Scouts themselves accelerated its demise.

Edited by tr-browsing on 02/23/2014 18:18:05 MST.

L Lanian
(Lanian) - F

Locale: California, U.S.A.
Heh on 02/24/2014 21:42:31 MST Print View

"Experience is what you get when you don't get what you wanted." - Randy Pausch

I'm still experimenting with gravity filters. I had always pumped before (with a one time infidelity with UV pens. Never again), and I absolutely loved the gravity type, but I'm still trying to find ways to cut back on weight. Hydration is a hard thing to cut back on, though, since it is so vital. I like have the ABILITY for high capacity, moreso than actually having high capacity.

I was considering ditching the bite valve part and just have the feed hose go to a bottle, perhaps with this:
But someone noted that adapter is ventilated (to allow better feed), which means it is prone to leak- not something I want while hiking (use in-camp being the exception).

So I'm wondering if I have the bladder (in my pack outside pocket), run by hose to the filter inline, from there going to a bite valve which I'd remove at camp and use as a gravity feed for basecamp. I'd use a .5L bottle/cup to drink out of while in camp.

So if we are talking grams here:
Gravity Works Dirty 4L bag= 82g
Hose to filter= 18g
Gravity Works Filter= 59g
Hydration kit (hose with bitevalve)= 58g

= 217g for a 4L capacity bladder with water filter capabilities- usable as both a hydration bladder and as a base camp gravity feed filter.

Pretty lightweight imo.

Multiple configurations
High capacity
Low weight

Possible leakage
Have to carry a cup/bottle for drinking at camp
Hard to backflush without a second bag

Am I missing anything?

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: Heh on 02/24/2014 21:57:07 MST Print View

217 grams seems incredibly heavy!

Maybe you feel that you need 4 liter capacity. Maybe you feel you need bitevalves and constant hydration and backflushing and the other complications. Also, I think the Gravityworks filter might be one of the heavier ones.

My current 2 liter gravity system weighs 7 ounces, including backup chemicals. Very soon, I expect to have that down around 5 ounces.


Glenn S

Locale: Snowhere, MN
Re: Heh on 02/25/2014 01:45:52 MST Print View

155g (5.5oz) for 2 - 1L Smartwater bottles, a sawyer mini, and a 2L squeeze bag.

4L capacity, Drink straight from a filtered bottle or filter into the other and add drink mix, gravity abilities, and with the Smartwater flip top, backflushing capability. A piece of hose and a valve, and you get inline 2L filtering too.

Edited by Glenn64 on 02/25/2014 01:49:02 MST.

Tony Ronco
(tr-browsing) - MLife
"seems incredibly heavy!" on 02/25/2014 11:04:13 MST Print View

LOL, ... upon reading that quote, I just flashed on the saying: The straw that broke the camel's back. (or the 1.65 oz in this case) ... Bob didn't mean it that way, but I just love BPL & the quote above, one of the many reasons why I paid my money to be here :-) By the way (a friendly disclaimer), there is absolutely no disrespect intended within the following post:

So, where did this extra 1.65 oz straw come from? (or ... what does it take to exceed the heavy threshold?) Let's get to the 1.65 oz first: the OP's 4 liter gravity system added up to 217 gm which is 7.65 oz.

Bob's "current 2 liter gravity system weighs 7 ounces, including backup chemicals" Aquamira repackaged into smaller mini bottles are approx 1 oz for both (depending on how mini is mini, could be less than an ounce for both). So for a more apples to apples comparison, let's call the weight of Bob's current system to be at 6 oz (w/o the chem treatment). The rest is simple math to get to that 1.65 "incredibly heavy" ounce straw.

In my mind, the questions about the weight are this:
1.) Is that 1.65 oz worth having double the potential water carrying capacity? (After all, water IS heavy). But, the OP stated he only wants that capacity for convenience in camp ... so,
2.) Is that 1.65 oz worth it to the OP to have double the water capacity convenience in camp?

But the difference in the weight can be bigger -
Bob's 2 liter gravity system will soon go down to 4 ounces (w/o the weight of the chem backup) ... which will soon yield a difference of 3.65 oz between Bob's and the OP's system.
Glen's 2 liter gravity system (4 liter carry capacity) is 5.5 oz ... It is not clear if that total included adding "a piece of hose and a valve, and you get inline 2L filtering" but let's go ahead and assume it does, then that yields a difference of 2.15 oz between Glen's and the OP's system.

What does it take to exceed the heavy threshold?

For myself -
My aforementioned "heavy/elaborate" (= 4 liter) in-line gravity / hydration system is 5.7 oz. But my lightweight in-line system (= 2 liter) is 4.1 oz.
Coincidentally a 1.6 oz difference too.

While a much lighter solution would be to go with chem treatment, that's not what this thread is about. (I personally don't like the taste, and I'm willing to carry a Sawyer mini to avoid that, AND I'm willing to carrying a hydration hose for convenience).

So, for those treks compelling me to carry more water (OY!!) I'm personally willing to carry that extra 1.6 "incredibly heavy" ounce because I'll need that double capacity. Philmont for example(which my son & I went to last summer). Also if I'm not compelled to carry more water AND I'm NOT going solo, I MIGHT be willing to carry that extra 1.6 seemingly "incredibly heavy" ounce in weight for
..., wait for it .... just for the mere reason of campsite convenience :-D

Edited by tr-browsing on 02/25/2014 12:10:33 MST.

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: "seems incredibly heavy!" on 02/25/2014 13:49:31 MST Print View

OK. Let me revise my comment. I felt like it was heavier than necessary.

In one respect, we have to have enough water carrying capacity to get us from water source to another. This year in California, that is especially critical, since the drought will have dried up too many water sources. I normally carry only about one quart of water where I go, but once in a while I have to carry extra. However, I almost never use my gravity system when out on the trail during a day, and I normally just use it in camp. Having all of your water carrying capacity tied up in one big container seems problematic. If it leaks or the wind blows it away, it makes a big problem. So, I generally keep my water in at least two containers.

We can cut our weight of backup chemicals by going to the water treatment pills rather than liquids. I cut some weight with the new platypus-style containers that I reported on previously. They weigh about 3/4 of an ounce for 1.2L volume.

"Bob's 2 liter gravity system will soon go down to 4 ounces"

I thought that I said 5 ounces.


Glenn S

Locale: Snowhere, MN
Re: "seems incredibly heavy!" on 02/25/2014 15:00:21 MST Print View

I guess I was trying to address more of the

Possible leakage
Have to carry a cup/bottle for drinking at camp
Hard to backflush without a second bag"

aspect of the post, while still maintaining a light weight.

And no, admittedly the hosing wasn't in the weight. That stuff is heavy and would add significant ounces. Multiple containers seems to most always weigh more than a single container for the same capacity. There are lighter bottle options, but then thread compatibility is compromised.

It just seems like a single water container is a weak link in the system. As long as you have a cook pot, then even filtration and purification can be improvised. But I'd be leery of putting all my eggs in one basket of carrying capacity.

Also, without any backflushing means, any of these membrane type filters will become practically useless in a very short time if you run into a lot of tannin tainted water.

Tony Ronco
(tr-browsing) - MLife
Re: Re: "seems incredibly heavy!" on 02/25/2014 16:55:07 MST Print View

RE: 'Bob's 2 liter gravity system will soon go down to 4 ounces'
"I thought that I said 5 ounces."

Yes, you are quite right sir! you did say 5 oz.
I stated 4 oz because I subtracted the approx 1 oz of chem treatment
(Aquamira repackaged into smaller mini bottles are approx 1 oz for both ... depending on how mini is mini, it could be less than an ounce for both).
Since you included your back up chem treatment in your totals for your 7 oz system, I assumed you also included it in your 5 oz totals for your new system, consequently I subtracted chem treatment weight off your new system, because I wanted the comparison to be apples to apples. (= w/o chem treatment included)

RE: Redundancy Needed?

Gentlemen, that's an interesting direction for the discussion! First let's note that we don't have redundancy in our shelter, sleeping system, or in the backpack itself, or our rain shell, or - etc, etc, etc

There are mitigating approaches for an emergency water containers ... our organizing bags / food bags (Freezer Bags) could be pressed into service as an emergency water container back up. our pack rain cover could be pressed into service as an emergency water container back up, just to name a couple ... and let's not forget mentioning the plain old simple restorative repair a piece of duct tape or vinyl tape can do to a pin hole. (But that solution would require carrying a repair kit *smile*)

Now, don't get me wrong - I fully understand the desire to carry the extra weight of a water bottle (1.2 oz). For me I carry one not out of the fear of a lack of redundancy, but for convenience. (There are other things I carry from "fear" ... an emergency fire starting kit for example). I find a water bottle particularly convenient at night when I want to drink which always happens at altitude for me. Or a very convenient vessel for my electrolyte drink ... if I'm in bear country I'll actually carry two bottles (gasp!) one for electrolyte and one without - plain water which I can have in my shelter for night time drinking.

Yup, those few ounces of extra weight are worth it to me for convenience ... and they don't exceed my threshold for being too heavy ;-)

... and maybe, (just maybe) they may not exceed the OP's threshold for being too heavy (?)


L Lanian
(Lanian) - F

Locale: California, U.S.A.
Concern on 02/25/2014 22:55:32 MST Print View

Ironically, my concern isn't so much for weight, as it is trying to get maximum usage of what I have (after all, this is a thread of multiple use gear)

I just felt it very redundant to have my bottles for water, a clean bag for storage, and the dirty bag/gravity works for filtering.

Consolidating them seemed like the logical choice, where I initially cut out the bottles and created a hydration bladder system from the clean bag. The question arose when I contemplated FURTHER consolidation, swapping the clean bag for a dirty one, and running the filter as an inline filter.

If I had the dirty bag with filter go to bottles, I'm essentially back to where I was- a dirty source and a clean container.

Playing devil's advocate here: how far is too far?

I can see @Bob's point of view- consolidating that much can lead to issues ... but isn't that what ultralight backpacking is about?

Granted, I'm fighting to get my gear below 13 lbs (because I just like stuff), so I'm not in the 'ultralight' range. However, I do enjoy the principle of using pieces of gear for multiple things.

To @Glenn's credit, the backflushing, or lack thereof, is an issue; and would appreciate any advice on how I could manage that with the setup I spoke of.

Glenn S

Locale: Snowhere, MN
Re: Concern on 02/25/2014 23:38:35 MST Print View

"Playing devil's advocate here: how far is too far?"

That's really up to you. When it comes right down to it, it's really all about comfort and convenience. Heck, you don't even need food for a simple 3 day weekender. People fast all the time and still manage to be active. You only "bonk" from low sugar levels when they were too high to start with. At least that's been my experience. ...but I'm drifting, so anyway.

I'd think a good compromise is in order. Use the system you have, then just add a small water bottle that you can rig up double duty as a backflusher. A generic disposable noname 16 oz bottle is under a half ounce. Rig up an extra cap as an adapter for flushing and be done with it. Those cheapo bottles can even be crushed down and blown back open several times without affecting integrity, so storage isn't even an issue.

Most importantly, don't look to anyone here for approval of your system. The best system in the world is the one that works for you! :-)