I'm testing out a DIY gravity filter based on the Sawyer SP122. I have a drybag for the dirty water container, ~3ft hose, the filter, and then a few more inches of hose to poke into whichever clean water container I'm using at the moment. I'm testing using plain tap water, and am trying to find out what flow rates I should be expect.
On my last test, it seemed like I was getting no more than a trickle of water through the filter. With the filter detached (drybag with 2-3L water, then just the 3ft hose), I got 16oz in 23 seconds. With the filter in place, I gave up after a minute and a half when it had only passed 1/3 that amount.
Any tips to improve my setup? How much water do I need in the dirty bag to provide enough pressure? Is 3ft hose above the filter sufficient? Do I just need to be more patient?