I thought it was important to move the surface of the water to oxygenate the water? Are HOB not appropriate for planted tanks? In future I may add CO2 system, when I have the funds and can figure out how to use one.
My penchant is for planted aquariums, so most anything I say will have that in mind.
Fish in the aquarium will use O2 and create CO2, plants will use CO2 and create O2 during the day.
Surface agitation in the aquarium is going to result in gases becoming equal in percentages as the gases in the atmosphere... I.e. air. ... So using a hob, or an airstone, or a regular sponge filter will likely increase oxygen and reduce co2 in a regular unplanted aquarium... But, plants will do the same thing, and there's a level where they want all the co2 from the fish, not for it to be lost... So it's a bad thing. If you inject co2, you are paying to do so... If that gets 'gassed off' then you are paying to add co2 to your air, and plants may not get as much benefit, unless you add more and more.
So unless you are keeping something that comes from fast moving, highly oxygenated, riverine waters, the chance is good that you don't need to have bubbles at the surface of the aquarium. not letting the CO2 from the fish stay in the water may enable more algae to grow, etc. So it's all really a big balancing game.
Your fish will be sure to let you know that they needore oxygen by gasping at the surface... So just pay attention to your fish.
