In my humble opinion, I would move that light that is right above the seedlings a little further away. It is too hot and too intense of light for the poor seedlings at this point. Your young plants needs low heat and low light for the first 2-3 weeks of life. Once they develop enough resiliency and leaves to absorb the light switch to your 400W and gives those babies just what they want and make sure the temps stay low. My first grow was in a closet very similar to yours and heat was a HUGE issue with my 400W light. That was with a built in ballast and no exhaust what so ever out of the room. You need to get low wattage fluourescent lights over those babies or perhaps some cfl's. The reflective stuff is good but mylar from your local grow store would be a lot easier and more efficient. More light is needed in the later stages of veg and flowering, not so much right now. Good luck to you and may your first grow be a great learning experience!