BWCA Prefilter Boundary Waters Gear Forum
Chat Rooms (0 Chatting)  |  Search  |   Login/Join
* For the benefit of the community, commercial posting is not allowed.
Boundary Waters Quetico Forum
   Gear Forum
      Prefilter     
 Forum Sponsor

Author

Text

sammyN
distinguished member (276)distinguished memberdistinguished memberdistinguished member
  
03/05/2017 02:21PM   (Thread Older Than 3 Years)
I'm making a gravity filter, but, would like to put a pre-filter in place, to remove particles/silt.

any suggestions on what I can do? Or where I can get something?

Thanks!
 
      Print Top Bottom Previous Next
Northwoodsman
distinguished member(2059)distinguished memberdistinguished memberdistinguished memberdistinguished member
  
03/05/2017 03:30PM  
I tried several different things. Most would just get clogged. What I found works best is a large filter bag. Pour the lake water through this or line your bladder with it before you fill it. Turn it inside out and rinse it in the lake.

Amazon.com has a wide variety of Nut Milk Filter Bags.
 
OldFingers57
distinguished member(4990)distinguished memberdistinguished memberdistinguished memberdistinguished memberpower member
  
03/05/2017 03:43PM  
Another option is, if you haven't made the dirty bag yet, is to have the outlet on the dirty bag up on the side of the bag some. If you put the hose outlet on the bottom of the dirty water bag all the dirt, etc. is going to go down into your filter. If it is on the side of the bag up a couple of inches from the bottom of the bag the sediment will go to the bottom after letting it sit for a while and you will get clean water. My MSR gravity filter dirty water bag is set up this way.

Also my MSR bag has a small fine mesh screen where the outlet hose is to collect large pieces of stuff.
 
03/05/2017 09:33PM  
I just use a bandanna , it does a pretty good job, and sure feels good when you put it back around your neck!!
 
03/05/2017 10:54PM  
bojibob recommended to me filter material for diesel fuel. It is fuel filter material/
It is a cloth and comes in various micron sizes. I would put it on the inside of the bag, where the water runs into the tube before the filter.

Here is a Link:


diesel filter material
 
03/06/2017 07:44AM  
Just made a gravity filter set myself.
The bulkhead fitting has a 90 degree barb so I just used a hobby aquarium filter sponge (poked a hole in the filter and stuck on the barb). Easy to remove, rinse, and replace. Lots of possibilities in hardware and hobby stores.



butthead
 
03/06/2017 08:59AM  
quote butthead: "Just made a gravity filter set myself.
The bulkhead fitting has a 90 degree barb so I just used a hobby aquarium filter sponge (poked a hole in the filter and stuck on the barb). Easy to remove, rinse, and replace. Lots of possibilities in hardware and hobby stores.



butthead
"


I also have a bunch or aquarium supplies from my reef tank and can get sponges cheap, but I would not use one as a pre-filter. They are hard to clean out and crap mostly just decays in there. Since it is finer crud, it will decay quickly and you will be pushing that ammonia and other toxins into your filtered water. Ammonia, nitrates and phosphates will not filter out and will go directly into the drinking water. The worst part is that you will not be able to get the crap out without a cleaning solution to break it down, so that means that rinsing it out while camping will not be effective.

Just use a mesh filter of some sort. A coffee filter, bandana, or something else that you can back flush or scrub clean. I prefer a 2 container system where you run it through a pre-filter before it goes into the bag for the main filter. Even a bandana over the top would do.
 
03/06/2017 09:28AM  
A1t2o, thanks for the info.
As it will only see lake-water and not recirculate water and pet fish waste I wonder if your concerns apply. I figured it is just a sponge and will be easily cleaned or at the worst the clogged sections cut off to expose fresh.
I looked more at the sponges easy fitting to the barb and it's ability to be removed for cleaning.
I'm not stuck on the sponge at all and appreciate you imput, thanks.

butthead

PS: Need to admit I was not looking for a prefilter, just picking odd supplies up at the local hardware and notices the term "Filter" walking around, so it seemed useful and found it's way into my basket-O-stuff. bh
 
Savage Voyageur
distinguished member(14414)distinguished memberdistinguished memberdistinguished memberdistinguished membermaster membermaster member
  
03/06/2017 11:29AM  
Coffee filter and a rubber band.
 
03/06/2017 12:10PM  
Butthead - I was mainly thinking of algae and pollen in the water. Probably some small bugs here or there too, but mainly plant matter. Those types of particulates would definitely be present in the water we filter.
 
BnD
distinguished member(810)distinguished memberdistinguished memberdistinguished memberdistinguished member
  
03/06/2017 12:28PM  
We use a Gravity Works Filter. It has a prescreen built in, however, the most useful thing we carry is a Sawyer Squeeze syringe to back flush the filter fast. Like everyone else we try to dip the cleanest water we can find away from shore.
 
03/06/2017 01:02PM  
quote butthead: "Just made a gravity filter set myself.
The bulkhead fitting has a 90 degree barb so I just used a hobby aquarium filter sponge (poked a hole in the filter and stuck on the barb). Easy to remove, rinse, and replace. Lots of possibilities in hardware and hobby stores.





butthead
"


Where did you purchase the tubing?
 
03/06/2017 01:40PM  
HighnDry,
Ebay It's the soft surgical silicone rubber type, I source many hobby things thru Ebay. The tubing and bulkhead fittings were left overs from other projects.

butthead
 
Grandma L
distinguished member(5628)distinguished memberdistinguished memberdistinguished memberdistinguished memberpower member
  
03/06/2017 02:54PM  
quote butthead: "HighnDry,
Ebay It's the soft surgical silicone rubber type, I source many hobby things thru Ebay. The tubing and bulkhead fittings were left overs from other projects.
butthead"

I am looking for the tube closure/slide to shut off the flow - Any source?
 
03/06/2017 05:11PM  
I used Camelback connectors and valves I had on hand, but home brewing supplies work well.

butthead
 
Loony_canoe
distinguished member (421)distinguished memberdistinguished memberdistinguished member
  
03/06/2017 08:27PM  
I have successfully used a small clear plastic gas filter as a pre-filter. The type used on lawn mowers. Can see if it clogging.
 
Grandma L
distinguished member(5628)distinguished memberdistinguished memberdistinguished memberdistinguished memberpower member
  
03/06/2017 08:48PM  
quote butthead: "I used Camelback connectors and valves I had on hand, but home brewing supplies work well.
butthead"

thanks - exactly what I am look for.
 
03/07/2017 09:20AM  
quote butthead: "HighnDry,
Ebay It's the soft surgical silicone rubber type, I source many hobby things thru Ebay. The tubing and bulkhead fittings were left overs from other projects.


butthead"


Thanks! Just picked up some.
 
03/07/2017 09:31AM  
I have never used a prefilter on my gravity kits, I just let them buck. I do however run a custom pickup on my large 5 gal setup. I've noticed that you often have two types of crud, stuff that floats and stuff that settles. Very little in terms of percentage is able to suspend in the water, mostly inset larva but even those tend to settle more than suspend. My pickup actually uses a small float to suspend the line about 3" from the top of the water level, it also keeps it about 3" off the bottom, picture a whiffle ball with holes in it. Not advocating this for smaller 2-4liter set ups as it would drastically reduce the water per bag full but it works wonders on the big dawg. I've run at least 750 gallons through my Sawyer filter, maybe even over 1000. 20-30 gallons a day is normal for my camping trips when I bring the big kit, we use filtered water for everything ,washing hands, cleaning fish, you name it. It is still fully functional and I have never used a pre-filter and have never bothered to get clean water away from shore. I always take the lazy route and grab it from shore. The more I use these filters the more I take short cuts. I'm 100% certain most slow filters are caused by trapped air. Once I started being mindful of airlocks and keeping it wetted I've almost eliminated my need for back flushing in the field. I might do it every 2-3 days now depending on use.

I have thought about adding a pre-filter, I mean what can it hurt, but my experience tells me they are certainly not 100% necessary in all situations, these filters seem to be able to take a good lickin.


As mentioned above the MSR and Platypus are nice as they put the pick-up port a ways up the side, seems to help a bunch.

Also I should note everything above is assuming you are using a quality filter like a Cascade Designs (MSR/Platypus) or Sawyer. Nothing applies if you are using the garbage Katadyn has put out, I bet you could get one of those to clog feeding it distilled water.
 
03/08/2017 12:04AM  
I used a fine nylon mesh bag I found at a brewing supply. This is the item. I have no idea what the micron level is but it did the job last year on a trip to BWCA and Isle Royale.
 
Saberboys
distinguished member(897)distinguished memberdistinguished memberdistinguished memberdistinguished member
  
03/08/2017 10:11AM  
quote Ragged: "I have never used a prefilter on my gravity kits, I just let them buck. I do however run a custom pickup on my large 5 gal setup. I've noticed that you often have two types of crud, stuff that floats and stuff that settles. Very little in terms of percentage is able to suspend in the water, mostly inset larva but even those tend to settle more than suspend. My pickup actually uses a small float to suspend the line about 3" from the top of the water level, it also keeps it about 3" off the bottom, picture a whiffle ball with holes in it. Not advocating this for smaller 2-4liter set ups as it would drastically reduce the water per bag full but it works wonders on the big dawg. I've run at least 750 gallons through my Sawyer filter, maybe even over 1000. 20-30 gallons a day is normal for my camping trips when I bring the big kit, we use filtered water for everything ,washing hands, cleaning fish, you name it. It is still fully functional and I have never used a pre-filter and have never bothered to get clean water away from shore. I always take the lazy route and grab it from shore. The more I use these filters the more I take short cuts. I'm 100% certain most slow filters are caused by trapped air. Once I started being mindful of airlocks and keeping it wetted I've almost eliminated my need for back flushing in the field. I might do it every 2-3 days now depending on use.

I have thought about adding a pre-filter, I mean what can it hurt, but my experience tells me they are certainly not 100% necessary in all situations, these filters seem to be able to take a good lickin.



As mentioned above the MSR and Platypus are nice as they put the pick-up port a ways up the side, seems to help a bunch.


Also I should note everything above is assuming you are using a quality filter like a Cascade Designs (MSR/Platypus) or Sawyer. Nothing applies if you are using the garbage Katadyn has put out, I bet you could get one of those to clog feeding it distilled water.
"


Do you have a photo of your set-up Ragged?
 
      Print Top Bottom Previous Next