"Dave" wrote in message
om...
I used to inject CO2 into my canister filter, but now use a Hagen
Natural Plant System diffuser. Hides easily behind some background
plants, no maintenance, works great in my heavily-planted 29g tank. I
can't say whether it would be adequate for larger tanks.


one of these units I believe is recommended for up to 20 g tank so for
larger tanks you would need multiple units. Lots of people simply buy the
diffusers and use DIY solutions.

Rick