Darktideanswered grow question 4 years ago It may be a slight amount of PH imbalance affecting the uptake of magnesium.
Calcium deficiency causes brown leaf splotches.
Magnesium show light green or yellow on the veins or edges, almost like striping and typically has red stems.
I use the below to check on symptoms and help diagnose my plants as it covers most everything.
https://www.growweedeasy.com/marijuana-symptoms
Great Luck & Happy Growing 🍃