that's funny you have that same leaf tip "burn" like I have on my GF end EB now. Can't figure if it's nute burn or heat burn. Cal-mag seems to help, Silica blast too. There's a science to pH levels that I'm figuring out now. Don't be disapointed by your yield with this grow. Your end result will be worth the time and effort. It' s a good strong sativa that keeps you up and going.