Question Marty, what size pump do you use to flood each tray? I had the similar setup (smaller in size 4x4 tray) with 20 plants with hydroton surrounded the cubes. work great but when I tried without hydroton I got bad results with loosing majority of the plants. I believe I messed up by not flooding at least 3/4 of the tray. Any feed back would be appreciated. Bud out