iron..maybe

try some ironite, 1-0-1 wont burn, its mostly a pigmentation thingi

otherwise they look great. Nute burn normally attacks the tips first (they will start to turn brown & get brittle)
also every other day for feeding nutes is too much. it takes about 3-4 days for nutes to get consumed & washed thru the cycle

also misting, can cause this. water on leaf's + light. Creates a microscope effect and burns your plant
growdemon Reviewed by growdemon on . Could be MicroNute def or Shock. Pick and diagnostic attatched. 295185295186295187 What is your experience level? (first timer, novice, experienced...) Novice Your Equipment: .1) Type and wattage of lights. (MH, HPS, CFL's, tube fluorescents, LED's) 400 Watt MH .2) Distance from tops? Approx 3ft from base of pot (65 days in the ground) Rating: 5