Surface agitation

[idris]

I've read that too much surface agitation leads to a loss of CO2. But also that it is good for getting O2 into the water.
Obviously both are needed, so any advice on how to get the balance right?

In the short term, I'm not planning on any flow pumps (Koralias etc) but are there any pros/cons to spray bars, having filter return outlets above or below the surface, tulips, etc etc when it comes to gas exchange?

 

[LondonDragon]

Just make sure it ripples and does not splash, have a look at the journal from Mark Evans, he has some videos of the rippling effect on his 120cm.