I'm thinking that's Mn and Mag burn, which leads to calcium deficiency as well. Dealing with burns are bit more of a task than deficiency's, you gotta transplant or just flush alot.
Also, if your PH is too low or too high it deprives the plant absorbing the right nutrients even if you have them available for your plant.
Get it checked!
(I've used MaxiGro before its great stuff. Too Good. If you know what I mean)