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Gravity filter/ hose length
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John Gelack
(jgelack)

Locale: North East
Gravity filter/ hose length on 04/12/2011 22:21:35 MDT Print View

I just finished my gravity filter. I am using a 2L Platypus as my dirty container, 46" of tubing going from the Platypus to a Sawyer filter, and about 10" of tubing going from the filter to the water bottle. I'm getting a flow rate of about 1 liter in 2 minutes. Filter weight is 5.5 oz. Does this seem good? Do you think I should shorten the tubing to save some weight? I would appreciate any advice you can give me. Thanks John

Brendan Swihart
(brendans) - MLife

Locale: Fruita CO
hose length on 04/12/2011 22:48:45 MDT Print View

My experience has been that having longer hose above the filter improves flow rate but hose length below the filter does not. When I use a gravity filter I only have a couple inches of tubing below the filter.

Ken K
(TheFatBoy) - F

Locale: St. Louis
You can probably go shorter. on 04/12/2011 23:21:35 MDT Print View

I've got about 24" above the filter (Sawyer 0.1 micron) and 5" below. I'm getting new-filter flow rates around 1:40/liter.

I think you can probably shorten up your feed tube and still keep the same throughput, but I wouldn't go below 18".

Ken

John Gelack
(jgelack)

Locale: North East
Thanks on 04/14/2011 10:21:41 MDT Print View

Thanks guys for your responses. I knew having a longer feed tube would improve flow rate, if I can get the same flow rate with a 24" tube as I'm getting with the 46" tube, that would be GREAT. I will also cut the output tube down to a few inches. Thanks again John

Gary Dunckel
(Zia-Grill-Guy) - MLife

Locale: Boulder
Feed hose length on 04/14/2011 10:55:06 MDT Print View



John, I originally used a 24" feed tube length with my Frontier Pro, and minutes per liter weren't all that great. Another thread indicated that flow rate was dependent on the height of the water column, which means tube length from the dirty bag to the filter. Most people liked 35-45". I settled on a 42" feed tube, and my output time nearly doubled from the 24" setup. So I would suggest that if you decide to shorten your tube, do in in 1-2" increments while you figure out what works for you. If you go directly from a 42" hose to 24", you might get a surprise you don't like. Then you'll have to buy a new tube and start over.

John Gelack
(jgelack)

Locale: North East
Good point !!! on 04/14/2011 11:35:33 MDT Print View

Gary, thanks for the advice. Now that I think about it, going from 46" to 24" in one cut, is a little drastic. I will keep experimenting with shorter tubing lenghts, (cutting in smaller increments) until I find something I'm happy with. Thanks again

Eric Palumbo
(palumbo) - F

Locale: Rocky Mountains
What am I doing wrong on 04/14/2011 13:45:33 MDT Print View

My flow rate is closer to 5:30/liter with 36-48 inches between source and filter. Why is my flow rate so much slower?

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

Locale: Silicon Valley
Re: What am I doing wrong on 04/14/2011 14:30:36 MDT Print View

It's hard to say what your specific problem is, but for some, the problem has been something like a big air bubble. Once you sort of "pump" a little water through it, the air bubble dissipates and it starts to flow better.

--B.G.--

Doug I.
(idester) - MLife

Locale: MidAtlantic
Re: What am I doing wrong on 04/14/2011 14:33:27 MDT Print View

"My flow rate is closer to 5:30/liter with 36-48 inches between source and filter. Why is my flow rate so much slower?"

Remove the filter from the packaging.......

Okay, seriously, is it a new filter? It needs purging first, I used to do mine in the shower. After the initial purge it should be much faster.

Travis Leanna
(T.L.) - MLife

Locale: Wisconsin
Re: Re: What am I doing wrong on 04/14/2011 15:08:39 MDT Print View

>After the initial purge it should be much faster.

Yes, and possibly after letting it sit and dry for several days as well. Many dry filters will need to be primed.

Eric Palumbo
(palumbo) - F

Locale: Rocky Mountains
Re: What am I doing wrong on 04/14/2011 15:21:17 MDT Print View

I've run many litres through the filter, trying to speed it up. Wouldn't that "prime" the filter? I've tried applying pressure to the feeder bag to pump water through it. That doesn't seem to work either.

I used the filter last year and I don't remember if it was any faster back then. But now it is surely just a trickle. Wondering if it's been knocked around too much and has broken tubules or whatever they are. Very frustrating.

I think I'll get a new one from REI. If same problem at least I can return it.

Travis Leanna
(T.L.) - MLife

Locale: Wisconsin
Re: Re: What am I doing wrong on 04/14/2011 15:23:36 MDT Print View

Eric, what filter are you using?

Eric Palumbo
(palumbo) - F

Locale: Rocky Mountains
Filter on 04/14/2011 15:26:36 MDT Print View

I'm using the Sawyer 3-Way Inline like http://www.rei.com/product/801824

Travis Leanna
(T.L.) - MLife

Locale: Wisconsin
Re: Filter on 04/14/2011 15:34:34 MDT Print View

Hmmmm, I just got that one myself, and with tap water, I can filter super fast.

Now, I don't mean to insult you here :)

But.... do you have the water flowing through the filter in the correct direction? I'm not even sure that would make a difference, but there is a "correct" direction of flow with that filter.

Edit: I just read that you used it last year as well. If the filter wasn't cleaned properly before storing, it may have developed some gunk buildup that is clogging the pores. Try using the sink attachment and backflushing it with some good water pressure. Let it run for a while.

I should also note that I'm purely guessing on solutions to this.

Edited by T.L. on 04/14/2011 15:40:44 MDT.

Eric Palumbo
(palumbo) - F

Locale: Rocky Mountains
Re: What am I doing wrong on 04/14/2011 16:14:16 MDT Print View

OK. Here's where I feel like a dork... no i wasn't running it backwards :-)

I have the old black faucet adapter (not the shiny new bigger white one) and i've never had much luck hooking it to any of the water sources in my house so I've never really gotten any kind of high(er) pressure through the filter.... until today. I took my kitchen faucet apart so I could get that POS adapter hooked up and pumped a ton of hot water through both ways..... EUREKA!

With my 36" feeder, I filtered (if you can call it that with tap water) 2L in 3.5 minutes.

Thanks for the thoughts everyone.

Edited by palumbo on 04/14/2011 16:16:24 MDT.

Rick Dreher
(halfturbo) - MLife

Locale: Northernish California
Re: What am I doing wrong on 04/14/2011 16:30:25 MDT Print View

Kudos on sorting it out. One thing I don't think was mentioned is hose diameter. The larger (1/4-inch+ I.D.) the better, depending of course on what hooks securely to the connectors. Sometimes, folks stretch on a small diameter hose and get poor flow as a result.

Cheers,

Rick

Travis Leanna
(T.L.) - MLife

Locale: Wisconsin
Re: Re: What am I doing wrong on 04/14/2011 16:30:43 MDT Print View

Another happy ending.

Glad to see it was something simple like backflushing. Though, that filter carries a lifetime 1,000,000 gallon warranty, so you probably could have gotten a new one for free.

roberto nahue
(carspidey) - F

Locale: san fernando valley
Not to hijack th thread on 04/15/2011 20:16:19 MDT Print View

But what's the weight with a wet filter?

Can you guys point me to a thread on how you make these gravity filter?

I'm currently setting it up with a fp and aquamira tablets?

Do you guys use any chemicals with your filters?

Thanks.

Zachary Zrull
(zackcentury) - F

Locale: Great Lakes
Re: Not to hijack th thread on 04/15/2011 20:25:26 MDT Print View

View this entire thread; there are a couple designs here.

I just read that some guide services boil, chem, AND filter. I suppose they're hiking on well-used track and have responsibilities (people).

roberto nahue
(carspidey) - F

Locale: san fernando valley
Thanks on 04/15/2011 20:48:28 MDT Print View

Zack.

I'll read that thread right now. Thanks.