Hey so I don't know much about soil but I'd say by looking at them, your ok to feed them. I use straight Coco and that has 0 nutrients so i have learned to charge my Coco with 1/4 nutrients for any new girls and during transplant. Also if your using straight Coco, you will need extra Cal-Mag or a grow nutrient that accounts for this. I use Sensi products from Advanced Nutrients which are made for Coco users. That ppm does seem high but I'd go with how your plants look and they look fine. Good luck!