No magnesium or calcium def going on they just look hungry. Cal and mag two different things two different deficiencies.

How long have they been in those cups? As TJ said they look hungry overall. I do see a couple leaves showing the start of mag def. That does not mean you are lacking magnesium. If your calcium is off it can mess with magnesium uptake. Epsom salts is my magnesium source. My light dose is 3/4 tsp per gal and my full dose is 1 1/2 tsp per gallon. If you are mixing the magnesium with anything else, and you need to do things in order. Any silica always goes first and then move onto your calcium and magnesia before inputting your nutrients. I like to pour out one cup of the gallon and mix my magnesium into that cup with a spoon then, once they the crystals are dissolved, I will put it back into the gallon.