My "Safe Water Anywhere" Gravity Filter System

All information contained is to the best of my knowledge.  There is no guarantee either written or implied that the system is safe or you will attain the same results.
All information and pictures are (C)Copyright 2001 Mike Tremblay All Rights Reserved.


Description:
This system is based around the Safewater Anywhere gravity filter.  This is a filter only and not a purifier.  It can be made into a purifier with the additional treating of the water with Iodine or similar purifying chemicals.  It is designed to be lightweight and easy to use yet, relatively fast.


Components:

Descriptions:
1 Platypus 4 liter "Big Zip" reservoir - This is a Platypus bag with a "ziploc" opening on one end and a hose connection and cap on the other.  The "ziploc" end is opened and used to "scoop up" the water.  The hose connection is used to drain it.  It comes with two "grommets" at the ziploc end to be used for hanging it.  I attached some "spectra 500" cord in a loop through the grommets and added a longer piece so it may be hung by the loop or, tied by the longer piece.  These ropes also keep the "ziploc" seal tight when you hang it.
2 Platypus hose connector - Adaptor to fit on the reservoir and allow the hose to attach to it.
3 4' of "Nalgene" hose - This can ba any kind of food grade hose. I use Nalgene because it is available from my work.
4 Safewater Anywhere inline filter
5 Platypus Duckbill drinking tube (tube, hose, adaptor,bite valve) - hose and bottle adaptor that comes as part of the Platypus "hands-free" drinking assembly with a bite valve.  I remove the "bite valve" and plug the hose into the outlet of the filter.
6 2.4 liter Platypus bag - Bag to hold the clean water. I usually carry 2 of these anyway.


Description on use:
1. Take the reservoir[1] with the cap on and open up the ziploc end.  Scoop reservoir into a source of water.  Try to find water without a lot of "floaties". Close the ziploc end of the reservoir.  Attach the "dirty" hose[3]and the filter[4] to the reservoir.  Hang the reservoir up as high as you can.
2. Attached the "clean" hose[5] to the outlet of the filter.  To get rid of air and increase the water flow through the filter, suck on the end of the clean hose for a bit then attach it to the "clean" water platypus[6].


Costs:
1-Platypus 4 liter "Big Zip" reservoir: $13.00 / purchased from Campmor / item #62926
2-Platypus hose connector: $3.00 / purchased from Campmor / item #55338
3-4' of "Nalgene" hose: @$2.00
4-Safewater Anywhere inline filter: $35.00 / purchased from Safewater Anywhere
5-Platypus Duckbill drinking tube (tube, hose, adaptor,bite valve): $10.00 / purchased from Campmor / item #12333
6-2.4 liter Platypus bag: $6.00 / purchased from Campmor / item #12321
Total Cost: $60.00


Weight:
1-Platypus 4 liter "Big Zip" reservoir: 2.7 oz.
2-Platypus hose connector: 0.3 oz.
3-4' of "Nalgene" hose: 2.1 oz.
4-Safewater Anywhere inline filter: 2.5 oz.
5-Platypus Duckbill drinking tube (tube, hose, adaptor): 2.0 oz.
6-2.4 liter Platypus bag: 1.4 oz.
Total Weight: 11 oz.


Filter Specifications:
From Manufacturer's Site:
High-efficiency, cleanable, stainless steel Pre-Filters that remove 99% of sediment,
 sand, mud and algae above 25 microns. This new Pre-Filter extends the life and
 efficiency of the Primary Filter and also lasts for the life of the unit.

 The Primary Filter removes microorganisms including 99.9999% of E. coli and other
 bacteria and 99.98% of protozoa including Giardia and Cryptosporidium. It also
 removes 99.8% of VOCs, pesticides, herbicides and petroleum by-products leaving you
 with safe, odor free, great tasting water. The Primary Filter will filter over 100 days (60
 gallons) of drinking water for an individual.

 Bacteriostatic Primary Filter prevents bacteria, mold or fungus from growing or blooming
 within the filter core itself.


My Tests in this configuration:
These are home tests with "home" tap water @60 degrees
Dry Filter test- Filter completly dry.
1: Filtered 2.2 liters in 4 minutes
2: Filtered 2.2 liters in 4:45 minutes
2: Filtered 2.2 liters in 4:45 minutes
Moist filter test- filter off and drained for 15 minutes but, still saturated
1: Filtered 2.2 liters in 4:30 minutes
2: Filtered 2.2 liters in 4:45 minutes
3: Filtered 2.2 liters in 4:45 minutes
Saturated filter test- Filter after sitting saturated overnight
1: Filtered 2.2 liters in 4:45 minutes
2: Filtered 2.2 liters in 5:00 minutes
3: Filtered 2.2 liters in 4:55 minutes

These are my field test with "wild" water @50 degrees
Dry Filter test- Filter completly dry.
1: Filtered 2.2 liters in 4:45 minutes
2: Filtered 2.2 liters in 5:15 minutes
Saturated filter test- Filter after sitting saturated overnight
1: Filtered 2.2 liters in 5:45 minutes
2: Filtered 2.2 liters in 6:30 minutes
3: Filtered 2.2 liters in 6:15 minutes
4: Filtered 2.2 liters in 6:45 minutes

These are field tests with "wild" water @50 degrees
Dry Filter test- Filter completly dry.
This was to be a 16 day test on Isle Royale. The filter plugged up after 5 days. I will post the data here soon but, I stopped using it after 5 days because it bacame a trickle! I think it was do to the sediment in the island lakes and could be used if I "pre-filtered" with a coffee filter on panty hose but, I have given up on the entire thing and gone back to my PUR.


Notes on testing results and why this configuration was chosen:
-The most important thing discovered in testing this system is the length of the "dirty" water hose.  In general, the longer this hose the better. I tested hoses in lengths ranging from 1' to 6' to filter 2.2 liters and found the following:
    1' hose @45-60 minutes / 2' hose @20-30 minutes / 3' hose @5-6 minutes / 4', 5' and 6' hose @5 minutes
So, the hose length increasing increases the flow up to a point then, there is no significant increase.  I settled on 4' because it is a good length to reach up and hang.  If you increase this to 6' you might get a bit better flow but, it is hard to hang that high and, it increases the weight.
-The outlet hose length makes no difference in the flow rate.  I tested this without any hose and noticed no difference in the flow rate.  The reason I use the outlet hose I do is because it is used as part of my "hydration system" with a bite valve.
-The water level in the reservoir seems to make very little difference also but, I did all of my tests starting in a filled state.
-I tested the flow rate with the ziploc end of the reservoir propped open to provide air flow and saw no noticable change in the flow rate.
-I tried propping up the "clean" platypus and laying it down and seen no noticable change in flow.


Maintenence and Other Tips:
-When you are done with your trip, make sure you set out the filter to allow it to dry out completely.  If it stays wet, "yukkies" could grow on it. I've also read of people "backwashing" it with diluted chlorine to kill anything before letting it dry out and be put away.
-You"ll notice that my "dirty water" hose coming out of the reservoir has a piece of red tape on it. I've also marked my "dirty water" cap with a piece of red tape. This way I never confuse a "dirty water" hose and cap with a "clean water" which is not marked. Don't want the yukkies getting into your clean water stuff!
- If you have time, once you fill the reservoir with dirty water let it hang for a bit so any floaties can settle to the bottom.  This will prevent them from plugging the pre-filter screen.


Links:
Safewater Anywhere - www.safewateranywhere.com
Campmor - www.campmor.com


Last Edited: March 20, 2002