Thanks for the reply milesm.
Hmmm... I already am running my co2 through my impeller.

I'm not a huge fan of the mist of bubbles, and I thought a diffuser might be more effective at raising co2 levels with less gas used. Is there any way to make this diffuser more efficient? This is the same model sold on the Aqua Botanic website, so I figured it would be pretty decent.
http://www.aquabotanicstore.com/Powe...usor_p/pd1.htm
Would it work better with a separate power head, like stated on the website?