[Lonely Angel]

I have a 20 gallon long tank that is divided into 4 sections (for bettas) and is planted. I'd like to add CO2 but I don't know if it will work properly for a divided tank. The dividers are made out of plastic mesh canvas (the kind used for crafts) so they allow very good water circulation. Can I just put the diffuser in one of the divided sections or do I have to use 4 seperate systems?

Thanks in advace to anyone who can help!