I have a total of 1.8 dwc indoor grows under my belt. Both have suffered nute burn. 1st grow ran at 50% recommended by mfg., still burnt. 2nd grow started at 50% nutes, lights at recommended 36" but at 40% power. Still burnt tips but the plants looked hungry. Over next couple weeks I cranked everything up. Nutes to 80%, lights to 90% and they seemed to love it. Still burnt tips. During this grow I had three extra plants outside in 5 gal pots with pro mix. They were feed twice a week with the nutes out of the dwc res. No burnt tips. Gotta have something to do with roots being submerged in the dwc. I don't know but planning on seeing burnt tips on all future dwc grows.