White spots on leaves

This is a calcium deficiency raising its head.... Can't figure out which diary this is from.... If it's the Giant, everything looks good (pH, nutes look good) so I don't think the calcium is locked out, just that the plant needs extra calmag... It's interesting because another grower with exactly the same nutrients has just asked this very same question with the same symptom... so I think there's not a whole lot of calcium in that nute line... Just give her some calmag and she should be fine... But don't expect that damage to be repaired... it won't be... you'll know if you've solved the problem if the problem doesn't spread. Those particular leaves will probably get a little bit worse over the next day or so but then it will stop getting worse... Good luck!