What type of deficiency is this??? with pics.

My plants are about 11-13 weeks old (not really keeping track) not flowering them yet and i just got a 1000 watt MH a couple weeks ago. Last week i noticed this dull greyish patch at the ends of some of my leaves and some brown-grey spots on another, i'm wondering what my plants are lacking or getting too much of. And also, one of my plants has some of its leaves, mostly the bottom portion curling a bit and id like to know what i could do about that. Im thinking its phosphorous but not sure, and i dont know what causes the leaves to curl inward.
Thanks.

I have some pictures sorry about the quality its a phone camera.