I have no idea what I am doing here but from what I have summed up this is what I cam up with. I hava tiny grow room that will support about 6 plants(my veggie room). I run the CO2 tank for 15 minutes at like 10 PSI. I keep the exhaust off during this time for about 2 hours and have it set for about 1 hour fight before the next cycle. THe exhaust runs all night with no CO2