CO2 for a 72 bow front

[robo-snickers]

So i found 2 32L soda stream CO2 canisters laying around my apartment so i figured i want to make use them for my bowfront tank which has only been set up for about 2 weeks.

I have kept planted aquariums before with success but never used CO2. What do I need to set up the tanks and how much would it be?. The tank is dirted if that matters as well as using two T5HO 48" lights

 

[dcutl002]

Here is a good thread for CO2: Pressurized CO2...Just thought I'd share.