Deficiency or Pigment?

Check for spider mites....if they are dark brown with orange ish circles around them....also could be a nitrogen deficiency

Looks like a cal mag issue to me but maybe another grower can give a better answer if your ph is in the right spot then it cant be that there are slight yellowing too so that could signify a nitrogen deficiency too. I would advise give her a feed and seeing how you go if your media is dry enough anyway :) good luck for a hearty harvest great looking plant :) Pigmentation will only really occur if the light is way too close to the plants bleaching them a white pigmentation but the most common is red stems and that is completely normal its just the plants reaction to intense light she turns red to help protect herself you will notice only leaf stem in direct contact with the light will gain pigmentation also pigmentation can accour naturally towards the end of a cycle and that is compleatly normal too shes just showing you her colours but this is very far down the line :)