Its always hard to tell from the pic with out the full environment and whats been going in to it. Honestly, I agree with the first comment that its chem burn. I saw you havent feed it but Ocean Forest can be very hot! I cut mine everytime I use it because I noticed burn the first couple times. If you cut with something like coco or the like it was also drain faster. I noticed in some of those pics that the leave curl like when over watered... this happens a lot with straight soil. I saw nothing that would make me think mites!