Do I Need Air Bubbles?

[netpox]

I have a 125 gal tank with a wet/dry filter. It has two over flows in each corner that drain the water into the filter and then filtered water comes out in 2 different spots into the tank. Do i still need to have air bubbles? one pet store guy told me yes and the other one said no because i have plenty of moving water.

 

[pippoodle]

as long as you have enough surface movement then you dont need air bubbles