hey there , i have to disagree with everyone here, this is a text book case of magnesium deficiency . Yellowing at the serrated edges of the leafs is the tell tale sign of this. "High quality genetics" like these seeds simply need cal mag even in soil. you can add it directly to the watering or use it as a spray. Do this and the problem will stop spreading almost immediately and the plant should be fully recovered in under ten days. Hope this helps ! ๐