Hello friends,

I have been paddling the BWCA for many years now and still searching for the perfect gravity filter for drinking water. I had a post about this a few years ago but still have not found the answer apparently. I used to use the Katadyn and the first filter worked great for a few years, but as most folks know they are now garbage as the past few have plugged up after maybe 1-2 trips and at $45/filter no way was I going to keep paying that. So I tried a cheaper one, Membrane Solutions, and that worked for a few trips but when I went up 2 weeks ago that did not work either so I had to boil water which took up precious fuel.

Is there a gravity filter on the market that is actually reliable? I just cannot believe filtering exclusively BWCA water would plug up these filters so quickly, not sure what is going on. Perhaps someone has a trusted set up? Or should I just carry an extra filter? I mostly go solo but sometimes have as many as 4-5 people, so I am normally not filtering a ton of water per trip. Heading up again next weekend and hoping to get some clarity.

Any advice is appreciated! Thanks all.

We use a lifestraw mission. It has never failed us and it is a purifier too. It can be backflushed with the attached squishy bulb. We always bring backup drops but never had to use them. The mission doesnt seem to dry out over winter like other filters do.

I use this system. It has never failed. Works great. It has lasted several years. It had good reviews from past threads on this site.

Platypus Filter

TomP: "I use this system. It has never failed. Works great. It has lasted several years. It had good reviews from past threads on this site.


Platypus Filter "

I also have a Platypus Gravity Works. On the second trip with it which was a year later I had forgotten about purging the air out and how often it needed to be backflushed and it got really slow. Once I did that it worked fine again.

My last trip it needed to be backflushed after every fill because the water was pretty dirty. I've been meaning to buy a second filter to have as a spare but keep balking at the $75 price. I carry tablets as a backup.

Drying out after cleaning is kind of a PITA too. Takes nearly a week to air dry. But all in all it still seems to be the best option out there and is worlds better than my old pump.

plmn: "

TomP: "I use this system. It has never failed. Works great. It has lasted several years. It had good reviews from past threads on this site.



Platypus Filter "

I also have a Platypus Gravity Works. On the second trip with it which was a year later I had forgotten about purging the air out and how often it needed to be backflushed and it got really slow. Once I did that it worked fine again.


My last trip it needed to be backflushed after every fill because the water was pretty dirty. I've been meaning to buy a second filter to have as a spare but keep balking at the $75 price. I carry tablets as a backup.


Drying out after cleaning is kind of a PITA too. Takes nearly a week to air dry. But all in all it still seems to be the best option out there and is worlds better than my old pump. "

Back-flushing is a routine procedure that should be performed with every fill-up. If you are waiting until the flow is retarded you are asking for trouble. You only need to backflush about a half cup of water to purge the air. Proper maintenance will provide a long filter life.

Agree on need to back flush. I back flush a liter after filtering 4. I also carry a collapsible bucket, and let water settle for 10 minutes before pouring it in "dirty" bag to filter. Many trips over many years on same filter.

I've had a 4 liter Sawyer gravity filter for about 10 years+ now and have replaced the actual filter in the line once. When I did, this is what I used and I have never had a problem.

A key maintenance tip for any water filter is to backflush and then run some water through with a tiny cap full of chlorine in the system, to prevent any bacterial or mold growth between uses.

https://sawyerdirect.net/collections/mini-water-filtration-system/products/sp128-sawyer-mini-water-filtration-system-non-peggable-cardboard-packaging

Another vote for the Platypus gravity system. Couldn't tell you what year I purchased it, must be at least 10 years ago, but still going strong. I replaced the filter once in that time. Very reliable piece of gear, especially if treated right as others have noted. My only complaint, as already mentioned, is getting it completely dry after a trip.

How do you fill the dirty bag with water? We leave it tied around a tree and use two, one gallon OJ or apple juice jugs. You can filter a lot of water that way very quickly. We don’t take the dirty bag to the lake. We dip the one gallon jugs in the lake and then pour the water into the dirty bag.

I have the Sawyer SP184 Complete 4L Water Treatment System. It works well. However, I do need to treat it with a vinegar and water treatment every now and then to get the flow back to normal speeds.

We bring up 15-20 men each fall for the last 16 years. We divide into 3-4 camps. We use exclusively Platypus 4 or 6 litre systems. As long as you back flush the air out (by holding the clean bag up higher then the dirty one) they work great. Very easy to sanitize when arriving home. We don't think any other filter is even in the class of the Platypus. (think about needing clean water for 20 men. . . .and how often you have to change the bags!) We have tried others but in the last 16 years only use Playpus

TomP: "How do you fill the dirty bag with water? We leave it tied around a tree and use two, one gallon OJ or apple juice jugs. You can filter a lot of water that way very quickly. We don’t take the dirty bag to the lake. We dip the one gallon jugs in the lake and then pour the water into the dirty bag."

Pour from a collapsible bucket. Easy to make a "spout" by pinching it.

A number of years ago I was excited to get a Basecamp filter only to be disappointed at how fast the filter clogged on the 2nd day of its first ever trip. Learned about a modification from this forum Filter Modification Thread I tried that and it worked well--still using it that way ten years later. I carry a plastic syringe with and we use that to backflush the filter with treated water about once per day for a group of four people and that keeps the flow rate of treated water good enough to keep our jugs and bottles full.

I’ve used a Platypus for about 10 years and have been pretty happy with it. It does sometimes run pretty slow which I think is due to air bubbles, but with a quick squeeze and back flush it restarts. Strangely on my 5 day trip last month it failed me - just no water coming through at all. I tried everything and could not get it to work. I believe I’ve taken excellent care of it with routine backflushes, bleach sterilizing, and drying. Maybe it was just its time. It was hot and boiling seemed a tediously slow option, so I just went out to the middle of the lake and filled the dirty bag and my Nalgene and drank it straight without problem. Despite this failure, I’ve had enough success with Platypus that I am likely to just replace the cartridge and keep going.

What makes the other filters better than the Katadyn is that they are field-maintainable by backflushing. It is essential to do that regularly to keep them working. There is a lot of other information available on various filter websites - Sawyer, Platypus, CNOC/Hydroblu, etc. and youtube videos. You need to let the filter thoroughly wet out when use it the first time and after storage. You need to avoid airlock. If you do those things it will last a long time . . .

Tomcat: "

Jaywalker: "I’ve used a Platypus for about 10 years and have been pretty happy with it. It does sometimes run pretty slow which I think is due to air bubbles, but with a quick squeeze and back flush it restarts. Strangely on my 5 day trip last month it failed me - just no water coming through at all. I tried everything and could not get it to work. I believe I’ve taken excellent care of it with routine backflushes, bleach sterilizing, and drying. Maybe it was just its time. "

It is possible that the failure is due to hard water deposits clogging the filter pores. These deposits are introduced when filtering hard water or end of season back flush cleaning with hard water.


Articles such as this address this issue."

This was really helpful and now my most likely cause for zero flow after storage. I have not heard of this problem before, but there are several cases out there to read about. I have Minneapolis city water which is relatively soft compared to neighboring suburbs, but I do have to run vinegar through my coffee pot every once on a while.

Most of the cases I found were for Sawyer filters, but I’m assuming the same holds for Platypus. I do find it a bit disappointing that the Platypus website does not mention the use of either vinegar or distilled water as a means to clear minerals from the filter before storage.

Sadly I can not test if vinegar can remove minerals as I tossed my filter cartridge assuming it was past its useful life.

Very simple to make your own. Dirty water bag on top, sawyer inline filter, clean water bag on bottom. Bring a syringe to back flush and you’re done.

My sawyer gravity filter is about 15 years old and still working with the cleaning, air lock prevention, and back flushing mentioned above.

Tomcat: "

Jaywalker: "I’ve used a Platypus for about 10 years and have been pretty happy with it. It does sometimes run pretty slow which I think is due to air bubbles, but with a quick squeeze and back flush it restarts. Strangely on my 5 day trip last month it failed me - just no water coming through at all. I tried everything and could not get it to work. I believe I’ve taken excellent care of it with routine backflushes, bleach sterilizing, and drying. Maybe it was just its time. "

It is possible that the failure is due to hard water deposits clogging the filter pores. These deposits are introduced when filtering hard water or end of season back flush cleaning with hard water.


Articles such as this address this issue."

Take it from the water guy here, ("we know water from the 'bottom to the tap' ") that while this is indeed possible, it's not likely much to be concerned about. Unless the water hardness is quite extreme--beyond levels I'm familiar with that would occur naturally--the amount of mineral introduced by an occasional hard water back flush should not cause any significant clogging. The hardness will likely be "in solution" and pass through the filter. Almost any lake water, which is the majority of what the filter will see, is hardness-free enough that hardness will not be the clogging culprit there either. Most of the clogging will come from from any not-in-solution microbes and various debris, both discernible and nondiscernible. That is why one has the filter in the first place and the clogging is showing that the filter is doing its job.

Old modified Katadyn user here. I take 2 Sawyer mini in-line filters on trips plus big syringe to backflush. Very satisfied with it. Good cleaning when I get home....run some bleach water thru it...rinse....extra backflushes....take time to dry in sun and air. Never failed me. When it gets a little slow, just backflush and off we go.

The Platypus 4L gravity system is totally reliable and durable. Take the filter into your sleeping bag with you from now on. Don’t allow it to freeze.

Good tip! Will try this!

Tomcat: "

Jaywalker: "I’ve used a Platypus for about 10 years and have been pretty happy with it. It does sometimes run pretty slow which I think is due to air bubbles, but with a quick squeeze and back flush it restarts. Strangely on my 5 day trip last month it failed me - just no water coming through at all. I tried everything and could not get it to work. I believe I’ve taken excellent care of it with routine backflushes, bleach sterilizing, and drying. Maybe it was just its time. "

It is possible that the failure is due to hard water deposits clogging the filter pores. These deposits are introduced when filtering hard water or end of season back flush cleaning with hard water.


Articles such as this address this issue."

I am going to try that, thanks for posting the link.

T

Waterdrop Gravity System is my group’s go-to volume filter. At under $40, including a long lasting filter (if you maintain it) you cannot go wrong. The replacement filters are inexpensive too, three for $24. Each filter has averaged one season of a minimum of five weeks processing water for four people and a couple long weekend trips for my wife and me. Quality water is a must. An inexpensive filtration system makes replacing the filter toooooo easy.

Waterdrop Gravity Filter

Impressive price and specs--can also get a two-pack...

TZ