00 Kush Indoor DWC

00 Kush - 00 Seeds Week 1 55L DWC 600W HID -------------------- I'm having troubles managing the temperature of the tent because it's my first run with sodium lights. That's the reason because the cotiledons have begun to yellow. I will stabilize it in the next days. -------------------- I have raised the light 10 cm more and I have achieved some degrees of lower temperature, but it is not enough. Right now the light is about 70cm from the plants and i have still 30ºC. Should I raise the light more? Or maybe buy a cooltube? What do you recommend to lower the temperature of the room?