In my experiences, light bleaching mostly happens when unacustomed plants are exposed to bright light too fast. Like going from young seedlings or clones that were under flourescents, to 1000 lights. best way that I have found is to put your young seedlings 6 ft. from the light to start and bring them about 6 inches closer per day until the temperature at the plant tops is no more than 80 degrees F. In cool weather the light will be able to be closer to maintain 80 degrees F than on hot days, when your growroom temp will climb. Calculate at the warmest time of day, usually near the end of the light cycle.
tokes2ya-Chummy