DT4
first, do you have any pictures of the system/setup?
Second, rockwool and
grow rocks have two very different property's. Thus by trying to keep the grow rocks moist, you can easily saturate the rockwool, suffocating the plants roots. You only want to keep the root-ball moist, not saturated. Rockwool sucks up and holds water like a sponge, but grow rocks wont.
Your best bet is if you started
seeds in rockwool and want to place them in grow rocks, to place them so they stay slightly (slightly) moist (near the top). The roots will grow down towards the moisture (away from the rockwool). If the rockwool remains saturated, you run the risk of stem rot. You want the moisture level to be about 2 inches below the top of the growing media. Even farther down if the rockwool remains saturated.