Originally Posted by bastage
The filter does not push against gravity. If the intake was low & just the output high then yes, but with both being sealed until it hits the aquarium which gives both sides the same water level. Your Atmospheric pressure also makes me lol since the only exposed atmosphere is the tank surface which its not pushing against since you are not raising the tank water level. The resistance of the tube is the only effect. Of which a change in materials from the standard rubber/nylon tubing can reduce.
Everything you just said is completely wrong. That is all.