Co2 ?

Just got my tank and regulator and I am ready to go......wanted to find out if I need to vent the room. I heard you just hook up the tube from the co2 to your fan and it blows it around evenly. If you are only adding it a few times during the light cycle, can't you have a sealed off room???

No, the air will quickly get hot and stale if you don't have some sort of ventilation.
I've not run co2 myself, but I believe most people turn the fans off during enrichment, then run them either constantly or timed/temp controlled the rest of the time.

i use Co2.. you definatly want a sealed room to contain the co2 while your enriching... i set mine to come on every 2 hours for 10 minutes, then circulate it for 20 minutes in the room, then my exhaust fan comes on till the co2 comes on again.. so 1/4 of their light cycle each day is co2 enrichment... i tape my tube to the back of an oscilating fan so that it blows the co2 and keeps it ciculating over the plants...

sampson