Gelato OG Clone Discoloration

Bottom picture was 2 days ago…So the bottom leaves were like this a few days ago. I cut them off, The rest were fine, but I woke up this morning to this.

I use 0 ppm water and add calmag and b52 to it to about 150ppm…I’ve fed it once using a feed meant for coco coir, so I’m ordering a feed meant for soil now. But idk what this is.

I’m looking through the grow Bible Robert Bergman wrote, and this kinda looks like Mag deficiency…If that’s