I'm growing 4 plants in a 3 by 3' tent. To of them are sour amnesia and totally fine but my other two cinderella 99 have what look like burn spots on the upper leaves. The spots are through the leaves and can be scene underneath. I'm using a generic grow kit from Baux. 600w White leds sitting about 18 inches above the top.

What do you guys think? Any help is appreciated. Amateur grower on his second crop.