It could be just that you have some Pythium wilt in those plants. Its very common with rockwool.

How are they doing today any new roots?

With the absence of odor and plant matter in your res then root rot is not the problem. When you have that its easy to find with your nose. So no odor then no root rot. Pythium wilt is a different story there is no cure for that.

I hope it's not that...it would suck.