Correct DWC water level for seedlings and throughout growth periods

thanks, that makes it a bit clearer.. given the rockwool itself isn't submerged, but the clay pebbles are, then you should be fine.. what's important is that there is some water getting to - but not being directly in touch with the rockwool.. in this case the clay should get wet and transport some to the rockwool.. just to make sure i would double-check to ensure the rockwool isn't drying out.. rockwool can keep water quite long, so in most cases it should be sufficient to wet it once and then it should be fine for a few days (most often the root will be out at that point)