What's a good CO2 system...

[Josh Q]

...for a 20 gallon planted tank? I plan on having it pretty heavily planted and heard it's good to have CO2 system.
-Josh

 

[CFC]

Where are you?UK or US?

 

[LesGerber]

a DIY CO2 system works great. I have one bubbling for three days and have already noticed growth..

Les