Usually mag deficiencies can exist for 4-6 weeks before you see any visible signs of it. That combined with LED that burns through Mg, and coco, which eats the Mg.... transpiration issues, light intensity..... the plant just presented suddenly, it didnt get sick suddenly. I think. I *think* thats whats going on. Ill have a better idea though once we get the stuff i asked for. (Humidity, temperature, pH and ppm both of the nutes AND of the runoff, and the brand/ration of nutes, how often fed, fed every time, ect...)