Help with Mag. def or Lockout or??

Modified supersoil (7 gallon smart pots)
35 Day veg
Day 46 flower (70 day strains)
1000w hps
RO water, CaMg+ @approx. 100ppm (General Organics) and Hygrozyme @5ml/gallon
PH 4.7-5.1 (I stopped adjusting my PH about 3 weeks ago because I'm organic!)
Runoff PH 6.6-6.8

Day temp. 73-78 Night temp. 68-70 RH 50-60%

This is my first real grow and I am growing two Kosher Kush and two OG#18's. The plants looked great with a minimum of 12 heads apiece and lots of flowers. It's gone without any big problems until today. The fan leaves are dark green but starting developing brown/rust spots as of this morning and the spots are spreading rapidly through the leaves of all four plants. These spots start either on the edge of the leaf or in the center and spread from there. It may have started on the lower fan leaves but seems to have spread throughout many of the leaves on all four plants.

is this Cal-Mag deficiency or Magnesium lockout due to PH or??

Thanks!!!

am i blind i cant see the pick mate?

Crystal orb doesnt work either.

Sorry... if I could figure out how to get the picture from my laptop to the thread I would post one... too much herb perhaps...

No yellowing... must be deficient in magnesium? I'm going to hit them with additional CaMg+ and a slug of molasses... unless somebodies got a better idea...