From stitchs Guide which was edited by SmknVTEC
http://www.icmag.com/ic/showthread.p...8&page=1&pp=15
This picture is what light bleaching/ light burn looks like.
The only way to fix this is to move the lights away from the plant!
Or, make sure you don’t go over 75 watts per sq foot, or your plant will have to much light and light bleaching can occur anywhere on the plant. Indica species seem to bleach easier From stitchs Guide
These pictures are what heat stress looks like.
The only way to fix this is to move the lights away from the plant, get better ventilation, and or add more fans! Heat - If the lights are too close to the plant, the tops may be curled, dry, and look burnt, mimicking a nutrient problem. Your hand should not feel hot after a minute when you hold it at the top of the plants.
Picture 45-46 provided by Mosfed