aeration

I have a small 200 gph pump (very low power usage) submerged in my pond for
additional aeration - just as added 'insurance'. The output is below the
water so the water is just 'bubbling' like a natural spring might. I do not
want it splashing for several reasons. I have been told it is the breaking
of the surface which helps to oxidize the water.
Questions: 1) Is this actually doing me some good. 2)Aesthetics aside would
an airstone attached be significantly better.
Thanxx
Bill Brister - Austin, Texas