those might even be the start of roots above your rockwoolNo not powdery mildew at all
Let me take a pic and I'll post it if one of them
Ya, it doesn't seem to be effecting them at all, still growing strong
Here's a pic
This one is the worst, it's covered, noticed it last night and separated it just in case
My 1st reaction was mold but looked around and all the pics of mold on clones I'm seeing look nothing like this