Reactor's work for all applications, DIY Co2 into a reactor would actually be a good idea, since it would preserve as much gas as possible.
But Thrak, DIY through a glass diffusor does not always work, usually there is not enough pressure.
Well, i won't try one of those then!

Any money saved is good. I have tried the diffusion through the airstone thing, but i would only get one large bubble through it, and it seemed to always bypass the filter intake. Perhaps i can try a different placement. Maybe securing the airstone directly to the intake screen with a rubber band....