Help, is this fade or a deficiency

Hey everyone-

Day 45 of flower. One of my ladies is showing signs of something. No idea what this is. Hoping someone can point me in the right direction.

Looks like a bit of a magnesium deficiency. Wouldn’t hurt to hit it with some epsom salt. About 1/4tsp a gallon should be good.


That’s what I was thinking. Would it hurt the flower if I left it or should I go ahead and just fix it?

Could hurt overall yield and terpines. Unaddressed and the rest of the leaves will look like that in no time.