Growing in coco is actually a soilless type of grow that is more a hydroponic method of growing. Also, it looks like you have calcium and magnesium deficiencies. Your pH is way too high also. So even if you were using the right amount of calmag, then your plant is locking out the nutrients because of the high pH.
@GIGIDURU, this is what I use to bring pH down. Only use a little at a time and mix well. Hydro Organics Earth Juice Natural Down Supplement. I also have the Natural Up in case my pH is ever too low.
https://smile.amazon.com/gp/product/B0052TF4OG/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1