Wet 4 inch rockwell cubes and put your clone (hopefully in a rockwool plug) in the center whole on the 4 inch cube. Push it down, make sure its conected good, and now when you put it under the rings it will get a kines o' nutrient.
I got my 8 babies growin in my table for 2 weeks now. I got my waterfarm yesterday, and putting it together. the shut off valves are a great Idea! Its half set up now, and will finish it off when my current crop comes out.. woo hoo.. Sounds like a good system