you should have an exaust fan changing the air at least once every 5 minuets and if you do you can get away with no co2, co2 will improve yeild but is not neededi'm growing in a 1m x1m ten ,i'm not wanting to spend a lot of money on some co2.will a big fan do?
that will do good luckgot 1,a grate big fan draws the air through a carbon filter cheers for the tips tho.i'll let you no how i get on