For starters, i think your rockwool is saturated in water (too much), the roots will not breath, and you could get root rot.

Is that a flood and drain system?
If so, try find tall 5" pot and use clay pellets between the rockwool and pots, keep the rockwool up as high as possible from the flood line. Next time you cut clones use smaller rockwool, so you dont absorb too much water.