Co2 controller please help me set it up right

Never used one my self but there is no need to have it on when lights are not on,plants do not need the same amount of air when the lights are off has they do when there on.My advice to you would be get in touch with a good hydroponic shop they should point you in the right direction.Also if you download see more buds there is a grow on there where the guy uses a co2 controler,think they area good buy if you get it right can in crease your yeild.But saying that i think has long has you have a good in let then these kind of grow extras can be done with out.A mate of mine got one a couple of years ago but now it sits dusty has he has gone back to 9 ince out let 6 ince in.Good look though i have just moved from my flat where i was tent growing,i had a battle all the time with temps,but still pulled 7/9 per plant.Just dont over do it when it comes to the ammount of plants max 2 per 600 hps.By doing this the bottom of the plant always produce good amounts that are normaly lost if you do too many under the one light.If you bought it new then the manual in side should tell you the right amount of co2 the room should need size wisei would hav eit on a timer and has long has you have a inlet that is giveing the plants fresh air then the co2 unit will add a bit of extra juice for the plants to intake.....................tyke

CO2 only at lights on and if you are losing that much Co2 I would check for air leaks either from your hood or fans or AC .