Okay, I have been reading alot of conflicting opinions on this topic. I know that I will need to have some sort of CO2 injection into my aquarium, how I will do this is still to be determined. I have however bought a Penguin Bio-Wheel 170 thinking this would be a great new filter for my planted aquarium. Later I read surface agitation will lead to the CO2 injections being worthless. However I have also heard that as long as the water level stays high enough, the agitation should be small enough that C02 injections would be worthwhile. Your personal thoughts on this would be great.