mottling on leaves

I've got one of three plants about 30 days from seed that is showing some weird color patterns/yellowing on the leaves. I don't think its a deficiency/bugs/pH because it has been there from the very beginning and I've taken measures against all of that. I've included a picture of the plant...

Second grow. Critical kush. 5 weeks veg. In 3rd day 12 12. Medium premier tech bilogical potting mix. Nutes. None in veg. 20 percent pnk nute with 5 percent nitrogen now. Light 600 watt castinoo led. Height of light 24 inches. Yes inches. Lol darn centimeters! These plants are growing well but...