Stonerdanswered grow question 4 years ago It's quite hard to determine the problem under that light, try under normal lighting so we can see the coloration of the leaf itself. If the damage is on leaves at the center and top of the plant then this is a Calcium (Ca) deficiency! If the damage is more severe at the bottom and has tip and margin chlorosis (burns) then it's a Potassium (K) deficiency!
In any way I'd suggest first checking pH levels of the irrigation solution and runoff(ideally 5.5-6.5) then increase the Calcium and Potassium Dosage in your fertilizers by about 30-50% (if calcium wasn't added then it's time to add with 1/4-1/2 of the recommended dosage).
Hope this helps! Good luck and happy growing :)