Gravity Powered Water Filter for Backpacking

Step 2: How to Use Your Gravity Filter

Now what do we do with this thing? It takes a little more thought to make this work that your average filter, but is pretty straightforward nonetheless. The main idea is to place the filter in a pot of water above the bottle (or whatever water container you are using) and allow gravity to move the water. The idea behind this is the siphon principe: http://en.wikipedia.org/wiki/Siphon. The steps to get his all to work are as follows;

1. Put filter in a pot of water above the bottle.
2. To start the flow of water, there must not be air in the hose, so suck water into the hose with your mouth
3. Place end of hose into water container.

Once the flow has started it will continue until the pot is empty. To filter more than one pots worth of water, simply add more water before the pot is empty and air enters the hose.

Tips for use:
Remember that your pot has touched unfiltered water, so be sure to heat something all the way to a boil before you eat from it!
This technique takes a bit longer than pumping, so its often most convenient to do in camp while doing other things like preping dinner.
To make the water move through the filter faster, increase the vertical distance between the filter and the bottle.
Even if you don't use this technique regularly, remember it in case your pump breaks- it has happened to me before!