Hi Mellow Man,

Pictures suggest you are dealing with Magnesium deficiency. To treat deficiency add 2 teaspoons of Epsom salts (magnesiun sulfate) per gallon of water/nutrient solution. For fast results, foliage spray with 1 gram Epsom salts per liter water . Greening starts at top of plant and moves downward. add same dose until symtoms disappear. Keep root zone and nutrient solution 70-75 F and your air temperature at 75F day and 65F night. Use full strength nutrient solution with pH balance 6.3 .