The video below shows an experiment with a sponge filter, where the big air bubbles are being spliced into thousands of tiny bubbles by a small Koralia circulation pump. The (possibly stupid) idea is that, there is 0.04% co2 in the air, which means the equivalent of 1 bubble every 2500 (of course the gases are mixed, but you get the idea). With the sponge filter pumping at least 10 huge bubbles per second, it means the equivalent of one huge co2 bubble every 4 mn. Not spectacular, but still, every little bit counts... and as you can see, there is no sign of algae, and all the plants are thriving, even the blyxa.... whereas in my other tank, that doesn't have the same system, plants are having a much harder time.
So what do you experts think ? Am I just being lucky, or is this indeed getting some more CO2 into the tank ?