Barrybee,
First I'll tell you why nobody has responded yet. You have provided crappy LED photos and no information on your grow parameters.
That being said I'll give you a couple of wild guesses...basically shooting from the hip.
First guess: You have overfertilized, toxified the rootzone and are locking out nutrients. Most dramatically K+
2nd guess: Slight nitrogen toxicity along with a well advanced magnesium deficiency
3rd guess: none of the above.
JD