Hi There

Dont worry about the yellow on the leaves, my biggest plant at the moment had
slightly burnt leaves when it was a seedling, now its a beast, go check them out :rastasmoke:

I have a 400w Metall Halide for Veg and a 400w High Pressure Sodium for Flowering. You should do the same, a HPS isn't so good for veg,not enough blue spectrum.

Anyways good luck on your grow =D
Peace