u wanna see what 1200 watt of hps can produce in a 4x4 room . look at the pic, the averages out at 75 watts per square foot. also i have my room mylared. as far as having too much light , well there aren't much brighter light sources than the sun and guess what weed nomally grows under it , so ur theory about too much light is kinda silly if u think about it , it sounds more like heat stress and bad ventilation that killed ur friends plant.