[Racefan]

they are 4 feet away from the light? Your only using about 1/16 of the available lumens if that. I place my 1000watt HPS about 12 inches away from my plants. You need to get it closer. If temps are a prob then you need to increase ventilation but to properly utilize your light you need to get it closer. I would put a light 3 or 4 feet away for brand new seedlings or clones but not established plants