Rockwool... Do I keep it soaked while germinating seeds? Or let it dry?

First time using rockwool. I'm using 1.5x1.5 size. So, they're small, and they dry out fast.

So, I decided to put the cubes into a container with like 1/4 inch of water on the bottom... Bad idea? The cubes seem to be staying soaked/wet. Is this bad, or is rockwool supposed to stay soaked?

thanks guys