what size is your room length, width, then heigth please? "A 400-watt HID deliversenough light to illuminate a 4x4 area well." This is straight out of Jorge Cervantes Medical Growers Bible.
400W HPS is perfect for you to flower under then. Less heat to worry about than the 600W. Keep to about 1sq/ft per plant 15 plants max. and you'll be very happy.