the reason i sak this question is becasue o friend of mine has that same exact setup that i posted the link to and it seems if he floods the tray that there will not be enough water in the resevior to pump more water back to tray and i know if you run the pump dry it will ruin the pump. me personally i plan on using hydoton for a medium and placing the plants possibly in 1-2" rockwool cubes. also the cubles should stay right above the water level correct or no. thanks for your input.