Hmmm, do you grow the same strain over and over, BWD? Or do you grow different strains at the same time? Or do you grow one strain one grow, and then follow it up with a different strain for the next? I'm curious, because, if this is something that happens to all of your plants regardless of strain, the constant would be your environment. I've noticed my plants have never seemed to mind the heat. Even when my closet was peaking at 92 degrees. They loved it. Very little heat stress. At night, temps are getting around the low 70s in there, probably. Maybe lower, when I have the a/c running. It could be causing it, could it not? I've heard of cooler temperatures causing purpling in plants, but I've never seen it first hand so I don't know what it looks like.