Don't spray water on plants with Hps or MH lights. It causes burns.

Please be carefull with the C02 in a people living area. CO2 is heavier than air and can fill up a room and will drowned you. You never see or know it's there. If you have plenty of ventilation no need of co2. You could run higher temps with co2 but then you need an ice probe or chiller to keep water temps down.

Not knowing what you have. You need an A/C vent going in low in the closet and a hot air vent going out the top of the closet.