That's a calcium deficiency but without a diary, I can't tell you WHY you have it... make sure anything you give her (water or nutes) is PH'd to between 6.2 and 6.5 so that calcium can be absorbed by the plant. Don't just throw calmag at it without checking your PH because if it isn't within range, you could pour a whole bottle of it on the plant and it wouldn't do a damn thing... the PH has to be in a range the plant can get at it...
Good luck.