Hi,
I am a little late in this thread but I had to post because of the thought that came right away. So you sound like you feed,feed water or regime like that. Remeber, you dont need to apply as much feed as the manufacture would post of bottle etc. So, it would not be hard to beilve it could possible be lock up. BUT I dont think so, you bulb is to close (in all respect) and your yellow chlorosis is uniformity working from the bottom fan or feeder leaves up. Your plants consuming themselves. Its either you have to up your nitrogen or your two or three part feed program. Or you dont, and need to flush if your pounding feed at the problem. I started a feed feed, water water. Seems to work just as good for me. Best of luck.
Also, I would not doubt the cal/mag since your plants look like nut hogs! Its not un common to see lots of people lacking that when in flower. Not in my cases but for many organic grows etc.