Cause of necrotic leaves

hey 👋 With your lower leaves yellowing and the new growth looking greener and healthier, it looks like a deficiency in mobile nutrients (in this case, I’d say magnesium and potassium); the plant is moving nutrients toward active growth. First, check the pH to make sure it’s not a nutrient lockout issue. If it is, start with a flush before resuming feeding. If not, increase the P dosage as a priority (the CalMag dose you mentioned seems sufficient, but if you do flush, give a slightly higher corrective dose during the first few waterings). Keep an eye on whether the new leaves stay healthy, the affected ones won’t turn green again, so judge based on the new growth. If the new leaves stay fine, the problem’s solved 👌

Looks like wind damage, is it near the fan?

I've had dead leaves like this on almost all my plants so far. They also look a bit older, and the fresh leaves look really good. So I wouldn't worry too much about it. No plant has 100% healthy textbook leaves. You pushed her a bit too hard a few days ago, but she made it through. Probably too much calcium. Or it's just part of her personality. Try to leave out the Cal/Mag and only give it back when you notice a slight deficiency. This shouldn't cause any further problems. She looks good, give her some time. 😊

Interveinal necrosis old growth is magnesium most likely from the antagonism of calcium, as Green Power Organic Fertilizer has lots of calcium already in it, with biobizz calmag on top has most likely skewed the ratio of Ca to Mg, which can immobilize other cations like Mg, giving the appearance of deficiency when it's "immobilized" through antagonism. Best guess I got, good luck.

Ca,P def