So I'm guessing you don't clean and sterilize your entire system between grows?
I have had soil grow white mold due too improper airflow but I didn't think this was a problem with Rockwool or coco
Wrap stays on during grow.why are they wrapped in plastic?
Yes. The soft block covers. You can actually see where the covers were.did you cover the tops of the cubes? like with panda film, etc