Help! This is my second grow -- the first was hydro and did not go well. I'm hoping you can help me this time.

This lady just started her second week of veg -- she's growing inside a grow tent in Fox Farm Light Warrior soil, under a 400w MH, which is 36 inches from her. Until tonight she's only had H20, but this evening I gave a half strength dose of Fox Farm Grow Big. She was started in a rapid root plug.

The grow tent should have pretty good ventilation -- 40w fan in the ceiling and a small box fan pointed away from the plants in the bottom.

She's Crystal Rain strain - I thought the yellowing might go along with the strain - but then I noticed some slight burning on her leaf tips. That's when I turned here for some help.