Platypus takes the hassle out of getting clean water on any journey with the GravityWorks 2.0L Filter System, bringing the speed of gravity filtration to a compact and ultralight system, perfect for solo adventurers and small groups.
Hmmm... maybe someone hasn't thought through the physics... You're better off having the filter as low as possible (i.e. at the collecting end), to exploit the increased hydrostatic head, thus pushing water through the filter quicker...
With a bit of luck, you can probably fix this by swapping the short and long tubing sections around.
Unless there's something very cunning about the filter that means it works better with a low HH, or breaks if the HH is too high, but that wouldn't give much design margin.