Planted Tank Guru
Join Date: Jul 2010
Location: Huntington Beach, CA, USA
I think the need for a bubbler may be misunderstood in many areas. It is an old standard that is still quite good. I gets water moving from bottom to topp and there has to be a certain amount of O2 into the tank water as the bubbles rise. But then the water is exposed to much more air at the surface than the bubble surface provides. This is where most of the gas exchange takes place.
Checking around, you will find many, many tanks will no bubbles but they do have filters set to move water from bottom to top. No bubbles needed but that does not mean that plants alone will get the job done. In tanks with no means to move the water, there is a good chance that it will pool in layers and spots in the tank may become useless for any fish.