Your setup is just like mine. You are already for CO2 now
2 ac hoods, 8" passive intake, 6" exhaust fan in a sealed room with a carbon filter.
I run CO2 until the last 2 weeks of flower and it is so simple
First take the filter out of the loop and connect your lights to the intake. If you want to you can run the filter as a scrubber but i find it unnecessary.
Next get a CO2 burner and a monitor/controller.( or bottled gas if you prefer)
Start running CO2. At the end of your cycle turn it off and connect the filter back up. the intake then refreshes the room air.
It does heat the room and I have to use a modified shaker unit to cool but it does not work that hard. With no ac it will run about 95f but I cool it to 85.