Hello Hydro,
What you want to do is get a co2 controller and raise the Co2 levels to the same ppm as your water.. (if you are growing hydro/aero)... you only use the co2 when the lghts are on. the controller should have a light sensor...
The room should be air tight and it should not take more than 5-10 minutes to get your room up to the proper co2 levels...
cheers - hope this helps