3rd week flowering purple and yelow leaves

i am using fox farms ocean/forest soil and fox farms big bloom ,tiger bloom in the 3rd week flowering and my leaves are turning yellow and purple and dying. what do you think i should do? check the pics.

no suggestions?

What is the pH of the run-off from your pot?

i dont have a ph tester.

tough to say but looks like she is hungry. that bottom yellow fan looks n deficiecny starting which is ok during flowering to a point. That purpling could be phosphorous, lack of n, cold nights, strain. I do believe I see some mg deficiency and K as well. what strength nutes are you feeding? and you def need to test your ph b/c if it is severly out of whack, which it may be, than you would get lockouts of these nutes. wallmart sells them. I would add some fine dolomite lime to your soil to help buffer your ph and add some mg and ca. or maybe some molasses.