Gravityworks water filter system

[Bob Gross]

I've used a Frontier Pro water filter in gravity-fed mode for a few years. This summer, as I was getting packed up for another trip, I could not find it, so I went to REI and picked up a Gravityworks water filter system which has two 4-liter Platypus containers. I used it with dual 2-liter Platypus containers on a five-day trip and then on a three-day trip. Mid-way on that three dayer, the flow dropped off to virtually zero, and I got water through it only by pressing on the raw water Platypus.

Now, either that is from a clogged filter element or else from an air bubble in the element. According to the instructions, either cause is cleared by backflushing the element for 4 seconds or until all air bubbles quit. Been there. Done that. It seems as though there was a small amount of silt inside, and it backed out into the raw bag. The air bubble still seems to come and go, so flow is totally unpredictable.

Any suggestions? I'm not too happy about the concept of buying a replacement filter element for Gravityworks. I mean, it has been used for only eight days total!

So, while I sort that out, I have rolled back to the Frontier Pro system. It is not such a fine pore size, but it seems to be more foolproof. Plus, it is field-maintainable. If it acts clogged, I can take it apart to blow out the prefilter.

Any Gravityworks fans out there?

–B.G.–

[Manfred]

Bob,

Last summer I took a crew of boys scouts to Philmont. We used a Platypus gravity filter for a total of five weeks during that summer (on different trips). During our prep hikes we had the same issue that the flow rate would slow down to a trickle. Once the scouts adopted the following protocol it was amazing how fast he gravity filter would provide water for 10 scouts without the waiting time that woud have been required when using chemicals.

1) After hooking up clean bag to dirty bag wait until a cup of water is in clean bag.
2) Now roll up the clean bag and force all air out of the gravity filter until no more bubbles rise into the dirty bag
3) Wait until all water made it from the dirty bag into the clean bag
4) Now force a cup of clean water back through the filter into the dirty bag.
5) Disconnect bags and empty water from dirty bag.
6) Enjoy treated water from clean bag

Forcing out the air (step 2) and the consequent backflushing (step 4) after each filtered bag made a huge difference for us and we were very happy with the gravity filter.

Best Regards,

Manfred

[Bob Gross]

Manfred, I think you and your scouts are right. I've been playing with this backflush process for a while now, and it is all a matter of moving the air bubbles out of the wrong places. Most of that has to do with interchanging the relative positions of the two containers, like you stated. After I practiced it about six times, it became more predictable. Thanks. I've never before had this much user problem with a water filter.

I find that some camp chores are tiring as it is, so I just like to expedite them as much as possible. I'll be gravity filtering for two people so that I don't have to break out the chlorine dioxide backup. Water flow in the streams has virtually dried up, so getting water becomes more of a crapshoot.

–B.G.–

[David Miles]

Manfred has the right protocol. It really needs the air removed ad the back flush with every fill.
They say not to drop the filter, but it is much tougher than they give it credit.
I've found that tapping the filter on a hard surface during the pressurized back flush releases a lot of sediment.

[Raymond Estrella]

http://tinyurl.com/8zrayqv

Bob there is no way you should need a replacement filter.

Try filling the dirty bag full of tap water at home. Run it through and shake it at first to dislodge any air bubbles. Before it runs dry stop the flow with the pressure clip.

Fill the dirty bag again but now run it into the clean bag.

Right before the dirty bag is empty swap positions with the bags so you are now backflushing. Go ahead and unhook the dirty bag if you are outside or in the bathroom where it can just run. Keep dumping more water to keep a good head pressure if you think there is a lot of gunk blocking the pores.

[Bob Gross]

Raymond, I agree. It is not a clogged filter element. It's just poor management of the air bubbles. Once I learned how to move them from place to place, it got much better.

Just to be on the safe side, however, I ordered up two new replacement Frontier Pro filters, and they are due for delivery tomorrow. So, I'll have backup systems in case of brain fade. I've never had to practice with a gravity filter before.

–B.G.–

[Bob Gross]

The air bubbles refuse to be managed.

I've tried this with both Gravityworks and Aquamira Frontier Pro filters. They work good only when they are brand new. Then within five or ten quarts of water, they are slowing down. Within ten or fifteen quarts of water, they are clogged and all flow stops. Note that the Aquamira filter has its own prefilter on the top end. I've checked that, and it always seems wet and clean.

I've tried all of the tricks by holding the clean bag above the dirty bag. It doesn't seem to work.

It doesn't seem to be an air bubble problem. Each filter seems to be full of water, judging by how much water I can shake out of them. I've purged the air bubbles out of the clean bag. Nothing seems to work.

Most of the time, the dirty bag is suspended at eye level, and the clean bag is at the ground level. I would think that is enough "head" to push the water through.

When I get desperate, I squeeze hard at the dirty bag. That will cause a spoon full of water to pass, but then it stops again.

–B.G.–

[Wolf’s Rain]

I have a new gravitworks 2l system that I was planning on testing out on a few trips in August. This thread makes me worried about their longevity.

[Bob Gross]

Yes, I use either filter element with a 2L dirty Platypus and a 2L clean Platypus.

I could understand clogging if I routinely scooped up suspect water. However, most of the time the water looks pretty clean, even though that can be deceptive.

I thought that I had it all figured out about the air bubbles and which way to manage them. Now, I'm not sure.

–B.G.–

[Joe Lynch]

We've been using a gravity works filter for three years without big issues with flow, maybe 20 nights for our scout troop. Did the filter ever freeze? That will kill it. Otherwise, try the manufacturer.

[James Couch]

About 2-1/2 years on mine. Probably have run over 100 gallons of water through the unit with zero problems. Never had the 'air bubble' problem. My routine is to treat my water and then some extra and back flush immediately after processing water.

[Jim Klazek]

Ray Estrella; I'm like you, no issues with the system at all in 3 years of use. I do have a question. If I add the Platy charcoal filter will the water back-flush through it from the clean source or do I have to remove it to do the purge/backf-lush dance?

[Author]

Posts