My System Consist Of A 2x4 Ft. Ebb & Flow Tray And A 20 Gal. Nurt. Tank Which Floods The Tray 15 Min. Out Of Every Hour. Water Depth In The Tray During The 45 Min Passive Period Is Approx. 3/4 In. Flood Depth Goes Up Gradully To Aprox. 2 In. I Grow In 6 In. Pots Filled With Hydrocorn Clay Pellets. the system is lit by a 400w hps system, the walls are covered in mylar. i use a small wall mounted circulation fan. i'll be growing stash seed at first to work out the kinks if you will. Im Starting Out With 18 Pots. i plan to kick the lights back 12/12 when plant height is aprox 1ft since i only have aprox. 4 ft. of head space to grow.........questions, what kind of nutrients should i use? when should i start using the nutreints? any other tips of wisdom that you think i could use, i bow to your expertise................thanks