Well done, sir!

You not only covered everything, you diagnosed it for us too. :thumbsup:

Seriously, I think you nailed it.
Looks like PH lockout to me.

Might wanna wait for a more expert opinion, though.
I'm jus' goin' by things I've read and pictures viewed.

(Best to limit important advice to stuff I have first hand knowledge of, yah?)

But your diagnosis looks spot-on and PH 7 is too high for soil.

I have yet to be in those shoes so I'll hang around and learn how to fix it here.

Aloha and good luck.
Weezard
Weezard Reviewed by Weezard on . 5th week flower and smaller bud leaves bright yellow Your Equipment: .1) Type and wattage of lights. (MH, HPS, CFL's, tube fluorescents, LED's)400watt hps w/4 25 watt cfl .2) Distance from tops?.. 12" .3) Reflector type? (cool tube set-up, bat wing, enclosed reflector, bare bulb...) cool tube w/reflecter .4) Is there a consistent fresh air supply? yes .5) Do you have an exhaust fan and a circulation fan? yes .6) What are the bulb wattages, kelvin ratings, and schedule? 500 watt all together on 12/12 Your medium: .7) Specific brand and Rating: 5