Advice for a large group gravity water filter

I use one of these:

http://survivalstore.com/r5s15lab2.html

with a sawyer gravity filter. A hydration hose that fits the sawyer will sit snugly in the spout of that container. It worked very well for us.

We have used the Platypus to good effect. The way they have the system setup it is nice and extremely convenient to use. Probably the most enjoyable filter setup I have used.

I have rigged up a Sawyer Squeeze that I picked up at a Garage Sale in the same sort of setup for my own use but have not had the opportunity to test it.

I heard that the Katadyn ones are less reliable and more prone to clogging than the new style of filter used by Platy and Sawyer because as they get more used they require more pressure, whereas the Platypus and Sawyer models are easy to backflush maintaining the flow output.

I used the platypus for many years and it is a great system. keep in mind it is a zip type system so it can leak. the great thing about it is that you can carry 8 liters of water with it (4 dirty, 4 clean).

About thirty years ago, there were not very many water filters in the backpacking market. So, we did what we could.

There was a collapsible five-gallon plastic cube for water. We threw a rope over a tree limb and hoisted the filled water cube up about 15 feet. Attached to the spigot of the water cube there was a vinyl hose that delivered the water down through a squeeze clamp to a filter element. That was a new gasoline filter from a VW Bug. So, basically we had a 15-foot head of pressure over the filter.

When one member of our group wanted water, he would squeeze the clamp which allowed the water to flow into the filter, and then filtered water came out of the bottom. VOILA!

No expensive parts. Not the very lightest in the world. Effective for a group. Everybody has to take turns carrying water up from the stream and hoisting the water cube up into the tree.

–B.G.–

The Platypus handles groups of 10 easier than other pumps I've used solo.
I usually go to the high sierra where I don't use one, but other areas with groups I love it.

I love my platypus gravity works. When I'm traveling solo I carry the "dirty" bag and hook it up directly to my hydration bladder with the Camelback Quick Link Conversion Kit and never have to take my bladder out of my pack. With large groups I use the setup as is and is a breeze.

> "So, basically we had a 15-foot head of pressure over the filter."

Or 6.5 psi. (15/2.31)

231 is such a useful number, I write it down three times for junior engineers:

231
231
231

And then I add the units:

231 cubic inches in a gallon
2.31 feet water head in a psi
231 mph – highest recorded wind speed at ground level, Mount Washington, 1934

Showing, once again, the superiority of traditional units.

I have used a Katadyn Base Camp gravity filter and liked it, except that the bag failed after a couple of years of light use. I was happy with the filter cartridge performance, and before that had used a Hiker (same cartridge) with very good results until the case cracked. So I like that cartridge, was able to clean it easily on the very few occasions it seemed to slow down, and the big bag on the Base Camp is great for a group- I think it holds a couple gallons – but don't expect the bag to last long.
I now have a Sawyer squeeze and am planning to rig it up for gravity use, but for a large group you'd have to confabulate your own arrangement of container and tubing and so on – and plan on very regular backflushing and a good prefilter to keep it running well.

Whichever way you go I would think in terms of several units – like one per 3-5 people – so that you have some backup and more convenience, and so that the first folks to reach camp can start filtering right away and not have to wait if the one person carrying the filter happens to be bringing up the rear.

We use the 4 liter Sawyer gravity filter for groups. I have only used it for a group up to 6 but it could easily handle more. Just fill the dirty bag hang it in a tree and let gravity do the work, plus the clean bag has an easy to use water spigot to fill multiple water bottles.

Thanks for all the advice! I decided to go with the 4 liter Platypys and ordered thru Moosejaw. I'll let you know how it worked out in a few weeks.

We've used the platy for three years with no problems for my scout troop. Great piece of equipment.

I've used the 4 liter Platy for years, has worked pretty good

Once the zip top opened in my pack, but it was just a test

After a few years it starts getting stiff and delaminating at the corners, but I used it a lot and it was gradual so I had plenty of time to replace

I like the handle – I've carried it for miles

It's kind of heavy – 2.5 ounces.

I'de rather take 3 one liter water bottles, 1.9 ounces, I can put them in my pack without worry of leakage

I just wanted to let you know that I have tried the 4 liter Platypus Gravity Filter on a couple of trips–and it is great! The first trip was with a group of 16 guys. It was really easy to fill. In some shallow creek areas we just filled a smaller container and poured it in to top the 'dirty' water bag off. And then it just went to work quickly, quietly, and conveniently. I especially liked the fact that no one seemed to mind going and getting water because it was so easy! When we used to have to pump filter our water it was often difficult to get recruits. So, I would say this a great product.

However, I am looking forward to the Mini Sawyer coming out soon. That should be great for my personal trips and maybe even the group trips.