Subject: Air pressure displacing water (revised)

Original question:
If you connect an air pump to an airtight container filled with water and place
a tube at the bottom of the water that leads out through the top, will the water
that comes out flow at a different rate when the container is nearly empty than
when full?
Picture: http://www.flickr.com/photos/51572554@N04/4742507144/
When I say air tight, I mean except for the tubes, though it is air tight around 
where the tubes go into the container. For the pressure provided by the air 
pump, assume constant, along with a constant volume of air flow. Really I want 
more of a hypothetical "Will it flow faster based on the height of the water 
column" than a "How much faster". Though if it does flow faster, any equations 
would be great. If you need to know the volume throughput, it isn't listed on my 
device and I don't have any way to measure it, other than the fact that using a 
2 liter soda bottle full of water, this setup will empty the water in right 
around 90 seconds.

Re: Air pressure displacing water (revised)