We took some risk and went on a short vacation right about the time the Simpson seedlings were to go into the DWC. I placed the rockwool into the net pots and surrounded with silica stones. I was concerned with light allowing algae growth as the added silica stone did not fully cover the rockwool to a depth enough to block all light. I decided to use the 6 inch black neoprene covers I had purchased a while back and they worked nicely.
Upon our return, we were pleasantly surprised that the leaf growth was enough to block the light so the covers were removed. The water level had barely changed and the PH remained at around 6.2. No change in over a week! Each plant has solid growth and at least 5 leaves. The stems are a bit longer than normal, but I did not have time bury deeper into the rockwool before our trip.
We left with the lights at about 2 inches above the tallest leaves in order to allow growth without fear of any type of leaf burn. The estimate was good as the leaves were not touching, but within a half inch of the bulbs. This shows that they had strong enough light for the week while we were out.
The Mesclun Blend is doing very well and grew over an inch vertically and at least two inches outwards while we were gone. We titled the light angle to accommodate both the established and new plants. This is the second get-away that the DWC proved to be maintenance free and the peace of mind is a real relief!
Pics to follow.