It's my understanding that water in aquariums is oxygenatied either by surface agitation via gas exchange or phtosynthesis. An excel tank or tank with no carbon enrichment has slower growth and presumably create less oxygen.

If this is the case would it make sense to increase surface agitation in a non co2 tank. ? I know many people keeping non carbon enriched tanks have little or no filtration.

Assuming one has a good balance of fish and plants, is surface agitation a plus ?

Henry

Some surface disturbance is good for any aquarium, because it does help with keeping oxygen in the water. It also helps keep the surface from becoming covered with a biofilm.

In a non-co2 tank, it also helps maintain stable co2 levels. Without good circulation to the surface, shortly after lights on the plants can totally deplete co2, then they become limited by the amount of co2 the circulation can supply (even more than they would be co2 limited otherwise). I think maybe this is at least partly why increasing circulation in non-co2 tanks can often greatly reduce algae breakouts, especially bba which is usually the result of fluctuating co2. That has been my observation, anyway.