I run CO2 in my 29 with 55 watts over it. I'm in rebuilding mode right now but the first time I did it, it turned into a very nice little tank.
I don't know if it will help with your algae, though. That's really just a battle of striking the right balance between light, CO2 and ferts. If you are
are going to add CO2, be prepared to add ferts as well.