Plants have enough nutrients of their own for the first 2 or 3 weeks of their life. You should not feed them till this point from what I understand. When you do begin feeding look for a mix of 20-20-20 or 20-5-10. Make sure the first number is the biggest - this is the Nitrogen Cannabis plants crave in their vegatative growth cycle. Is that reflective material creating hot spots on your leaves? It may do that because it beams lights at particular spots instead of just reflecting -you could try white-works best I hear.