OK so im looking into buying a 400w hps with cool tube. What size fan will i need for the tube? How close can i put it, or do I check that by burn? I hear Nasa and so forth uses gh flora products anyone use a very simple ph ajusted nutrient system that you can do easily? Im looking at contructing my own aero-ponic system i found on this site. not a first time grower i have had 4 attempts at growing out side and only 1 harvest but i have learned alot, and save some money. Then realizing security is an issue were i live decieded to move my hobby indoors. so basically Just need some plain help chooseing what i need to buy before i get all into it. Thanks