Yellow - Brown Leaves / Brown Spots

I would say it’s a cal mag deficiency 🤔

The ones yellowing from bottom up is N-deficiency (pic 4 is good example). Looks like you got a couple with Ca deficiency sprinkled in, too (the ones with spots). if you have a hot spot where that plant with the yellow leaves on top, the light might be part of the overall issues seen. your petioles are red, your veins are dark.. these are signs of issue related to your fertilization. More than one thing is out of balance, even if the symptoms are not as obvious beyond the N and Ca issues. the plant yellowing at the top doesn't make sense, so the light intensity in that area is the first thing i'd look into. Looks more like cannabilization than a typical symptom progression. The balance of nutes is impossible to assess with soil.. what is provided by soil vs what you add with fertilizer is different in every garden. wow that really progressed quickly the last 7-14 days, huh? The plants on the left more so than the right. In future you'll want to react sooner to the symptoms. Once they start to progress it won't just stop. it means that what you and your soil provide is not keeping up with how much is used. Be patient, but also don't wait 2 weeks when it's going downhill at a noticeable pace. also remember that Ca and Mg are two different things. just because there's a popular product named "cal mag" doesn't mean they are intrinsically linked to each other.