Phosphorus Deficency

I was hopin someone could help me out with a Phosphorus Def problem. What it would look like in the veg state and how to fix it. Ive read a little bit and found 1 person who had the same problem, heavy darkining of leaves. Any help would be awsome. Using promix pro medium and ff nuts. 85degree constant fresh air and exhaust 400w mh. Any suggestions?

the leaves are now starting to schrivel up, but they are dark green. Stunted growth as well. can anyone help?