Gravity Filter

Edited out first section — error on my part (sorry, Chris).

Which of the following qualitative water treatment do you require?

1. improve water clarity
2. improve water taste
3. remove protozoa (crypto, giardia, etc.)
4. remove bacteria
5. neutralize viruses

Do better than 1 LPM.

The HyperFlow does 3 LPM. The "lowly" Sweetwater does 1.25.

Even newer Gravity Filters do better than 1 LPM. The AutoFlow (MSR) does 1.75 LPM, and the Platypus does 4 liters in 2.5 minutes (which is about 1.75 LPM I think). The ULA Amigo Pro does 1 LPM.

So no, I don't think that asking for a gravity filter that does at least 1 LPM is asking too much.

The "lowly" Sweetwater is actually the fastest of all MSR pumps — until the Hyperflow came out. But like you, I am unimpressed with the Hyper — the great flow rate comes at the expense of a carbon element — meaning the Hyper won't improve water taste.

My bad on the ULA. The three factors I am most impressed with:

1. 1L flow rate — that really is fast for gravity feed.
2. 0.3 pore size — great compared to the 2.0 Seychelle gravity feed and the even bigger 3.0 Frontier Pro.
3. carbon core — this is one of my "must have" requirements.

Of my list of 5 qualitative factors up above, the ULA can do everything except the last item — treating viruses. If this is not a concern (and it isn't for many hikers) — the ULA looks like a winner. OTOH, if viruses are a concerned, then you'll want something else.

Chris
I use the ULA Amigo but replaced the PUR filter with a Sawyer
SP120 that I attached a couple of feet below the bag. It is about 6 1/2 oz dry.

Remove particulates, which is also helpful in water clarity, though I understand won't make my water clear. Clear water requires charcoal (from what I understand).

Remove all but viri (I don't hike in what I would consider dangerous areas for the contraction of viruses). Bacteria and other bugs are far more worrisome for me. That said, I'm looking to get down to as low as .02 microns, which is surely possible. At least 2 of the 3 filters I mentioned, The MSR and Platy, filter down to .02. The ULA might as well, but I'm not sure.

Water taste is an issue, but too much of one. Most mountain water is pretty good without the aid of charcoal.

The MSR uses the hollow fiber tech, but if I'm not mistaken, that's part of the problem with the HyperFlow. I haven't read the widespread bad reviews with the AutoFlow that I have with the HyperFlow, but then again there aren't many reviews to read that I've found. Ditto with the Platypus.

If viruses are not a concern, then 0.2 / 0.3 micron is more than enough to handle the rest (bacteria and protozoa). All MSR and Katadyn pump filters have that pore size.

You wrote .02 above — not sure if that's just the decimal in the wrong place or you really want pore size to go that small. Going that small is unnecessary for protection against bacteria. Indeed, the pump / gravity filters I know that have pore sizes that small are the First Need Purifier and the Sawyer Purifier — which you really don't need if viruses aren't an issue.

With an inline filter, it is really easy to make your own gravity filter system. I use an inline filter for "Drink as you go" filtering (stop at a stream, fill the platypus, drink through the filter, empty out the rest). This saves weight (assuming you cross enough streams). For camp use, I attach a hose onto the platypus and connect it to another platypus. My "dirty" platypus has cord connected to the bottom, which allows me to hang it (and also makes it easy to determine which one is the dirty one). You may have to "burp" the system, but this works well.

Ross:

My own set up allows for use as both inline and gravity feed as well. To me, having that option just makes sense because we don't always want to wait while the water filters its way from dirty to clean pouch. During the day, it's often much easier to just scoop the water, then be on our way and drink 'on the go'. To me, gravity feed "shines" when used at camp — when larger quantities of water are needed but time is plentiful.

I would have purchased the ULA Amigo in a heartbeat if it had connecting "nipples" on both the "in" and "out". That would have enabled its use as both inline and gravity feed. But alas, no.

I agree Ben, the "drink and go" method is underrated. Of course, it only works in areas that make sense. Where I do most of my hiking (in Washington State) it makes sense in the Spring and early Summer, but I have to be careful in the Fall. Actually, I have to be careful year round, but in the Fall I know I'll have to carry more water.

Chris & Ben,
I have the ULA H2O Amigo gravity filter but have replaced the filter cartridge with the Sawyer SP135 filter. (The one that is effective on viruses). This is my treatment of choice when hiking where the water is cloudy, such as the swamps of Florida.

In mountain stream areas, I use the Steripen Adventurer to save weight. I don't have confidence with the UV light system in turbid waters.

Then again, in winter, I don't use a filter system because I'm afraid of the internal filter being cracked from freezing, which would unknowingly render it ineffective.

So, just like a backpack, tent or stove, one item doesn't work best for all situations. Which, I guess, gives us gear heads something to discuss. :-)

Here is a way that I use my Sawyer on the trail to drink and go without hauling out the gravity filter.

I agree with Ben, the gravity filter works well in camp.

How to use Sawyer Filter on the Trail or Day hiking:

1. Only use Sawyer Filter (1.8 oz), Platypus Filter Link and 1 oz. disposable 1 pint/500 ml water bottle

2. When hiking on the trail and you want a fast drink of water without having to use the full system, fill 1 pint bottle with dirty water

3. Screw on Filter Link/Sawyer Filter loosely to 1 pint bottle

4. Turn bottle upside down

5. Use bottom of Sawyer filter as a straw to suck water from bottle through filter

Note: Loosely thread the Filter Link/Sawyer Filter. As you drink water, you should see a steady stream of air bubbles rising in the bottle.

Threading the Filter too tightly to the bottle will create a vacuum as you drink, which will collapse/crush the bottle and slow the flow.

Seeing the air bubbles rising in the bottle is an indication that you have not threaded the Filter too tightly.

Hope this helps.

-Tony

Whoa, guys- I have no idea where I've been on this one, but the Sawyer unit sounds awesome! Just checked it out, saw one site that has the weight at under 2 ounces. Sheesh! Guess I know what I'll be doing for water treatment.

(Edited b/c I mentally swapped sweet/sawyer)

The Sweetwater weights in at 11 oz.

http://www.msrgear.com/watertreatment/sweetwater.asp

I used mine for the first time this weekend. I filtered ALOT of water and it never slowed down. An MSR rep told my local outfitter that the problems are due to people not backflushing regularly. He said they're finding that the filter has nearly an unlimited life when maintained properly.

Hi Roman

> An MSR rep told my local outfitter that the problems are due to people not backflushing regularly.
That's what the rep said …
Read the review just published for a different take on that.

cheers

I've used this filter without any issues and very little backflushing, maybe the water was not fowl enough (not a duck in sight). I will hope that future versions this little filter can be improved to handle more disgusting water without the issues described in the BPL review.

One thing I'm wondering about the Sawyer inline filter thing… It seems like it's using the same microporous tubes that the Hyperflow has. I've had nothing but bad feedback on Hyperflows in the store, and I've personally found that the backflushing etc doesn't seem to work for beans. For those of you using the inline filter, have you had problems with it clogging? Yes or no, how many gallons have you put through it? My thought process is that since the water isn't being forced through with pressure (greater than gravity), perhaps gunk doesn't get jammed into the pores?

What is the Sweetwater inline filter? I know there's a Sweetwater pump filter and also an inline prefilter… The prefiliter is only good for blocking out visible sediments. Am I missing something here?

Brad,

I have been using the Sawyer in line filter for 2 yrs now and I have never had a clog or a noticeable decrease in water flow. (I have been taking a trip about once a month for a weekend or longer for the past year and a half, so I have put a lot of liters thru it).

I have a detailed review of the Sawyer Filter on the user reviews here, if you want more details.

I have not had to backflush mine in the field, but once I get home after each trip, I backflush with water mixed with a few drops of bleach to clean out the filter, before storing it for the next trip.

Based on that, I see no reason why I could not backflush in the field with clean water.

If this matters, I also use the Sawyer filter on the trail like a straw, so I am "forcing" the dirty water through faster than a gravity filter. I have even sat on my 4 L Platypus water tank to speed up the process of pushing the dirty water through the filter with no problems.

Having said that, I have been very careful to use water that is as "clean" as possible.

I have yet to try to push muddy water through it….I have pushed green water in it.

The only major drawback with this filter is that it does not have a carbon element to it to improve the taste of bad water.

To do that requires adding something like a Katadyne carbon filter cartridge, which gets bulky and add significant weight, but does work.

I used this combo this past week in Big Basin, CA….near the ocean. Water was really suspect for all sorts of contamination. The carbon cartridge did not slow the flow of water at all….pleasantly surprised on my part.

P.S. Ben: I am with you. I have never heard of a Sweetwater inline filter/gravity filter. If you are missing something, so am I.

-Tony