What is wrong with my lady’s??

FF nutes pro mix and espionage soil mixed always water with water 6.2 to 6.6PH they are at the end of week5 of flower and appear to be stacking nicely and praying to the light. I was thinking the pink/red color might be from when the lights are off and it’s getting to cold?? But the spots got me stumped the plant in the back has been off color the whole grow no matter what I do. Still stacking nicely though. Any help you can give me would be appreciated.

That red colour could be from the cold temps at night

and those dots could be from not giving them cal-Meg try giving some cal-mag from fox farm it’s the company your dealing with or find what ever suites your needs I deal with emerald harvest and the results have been crazy hope this helps