Can I get a few peoples description of the gas exchanges taking place on surface.

[StoutLager]

I was told that there are very important gas exchanges going at the surface of the tank. Can I get some descriptions of the chemistry going on here. Thanks.

(I know there should be a powerhead or something that stirs up or breaks the surface tension to help this. I also have heard that you should not have a glass cover on your tank for this reason too)

[Paintbug]

the main one is the CO2/oxygen exchange. the reason you want more surface aggitation is to create a larger surface area. lots of small waves has more surface area than a flat surface. this also keeps the less oxygen rich water moving in the tank. the reason most will say not to use glass tops is it doesnt allow the CO2 to exscape as quickly, and can cause the waters PH to drop. Randy from the chemistry forum can probably add more if you want to ask him.

[Blown 346]

Alos having the waters surface broken up will aid in the removal of proteins in the water.
But Paintbug pretty much sumed it right up.