I always get tip burn, as usual the single leaf is gone before the cotys fall, love some fat green cotys, a good sign for me. The three leaf fan is next, I call this node 1. The first 5 leaf fan will turn next and the tips with the following initial fans will brown up to the 3rd node. Usually it stops because nutes get less and less and the burn stops(mobile nute)???. My personal lights are small 200 watt sf on 75 percent.