Deficiency? Toxicity? Something I’m missing?

I’m in mid to late veg and my plants just took a quick turn within a few days. They’re being given cal mag and have been about 2-3ml per gallon. Soil grow (FFOF) which is also running seaweed extract and veg nutes (FF grow 10ml per gallon and 6ml bloom). Catchers are clean. Some leaves are necrotic, more so the lower ones, top fan leaves have gone south within a few days. No visible pests. Soil ph and feeding/watering are both about 6.4/6.5. The temp and humidity are good 69 degrees at night 72-73 during day, so I’m stumped. Switched to an electric sky which is 30 inches at 30-40%. I’m just going to water them straight with cal mag as I have been since it’s soft water, until I figure out what’s going on. I appreciate any thought.

It's hard for a doctor to diagnose a sickness and prescribe proper meds over the phone

They look fine to me