Quote Originally Posted by rfeiller
if you have a submersible pump you can install a pvc "T" at the outlet and run a tube from above the surface to the verticle portion of the "T" turn on the pump and the discharge water with draw air from the surface and discharge air with the water. aquarium power heads used this method to force additional O2 into the water.
It's called the Venturi effect. Here is a link http://en.wikipedia.org/wiki/Venturi_effect or http://www.unu.edu/unupress/unupbook...e/80A01E08.htm