Well for a "novice", you seem to be pretty on top of your game. Ph is good and everything, IMHO.

Except the amount of ferts/food u r giving it. seems to be a tad higher than what i would recommend. Try doing it less. thats sadly all the advie i can give you

-G

p.s: i have the same problem with my plant. It was turning yellowish green at the tips, then it turned brown and died at the tips. And only on a couple leaves at the bottom. The problem was not overfeeding, persay, more that i mixed two kinds of miracle grow soil. not the smartest move at all. =) nevertheless, it WAS a fert/food problem. I resolved it with a soil change. expensive, but effective
GD12345 Reviewed by GD12345 on . Nute burn? Pictures/troubleshoot included What is your experience level? NOVICE Your Equipment: .1) Type and wattage of lights. T-5 .2) Distance from tops? 2 IN .3) Reflector type? T-5 SET UP .4) Is there a consistent fresh air supply? NOT AS MUCH AS ID LIKE...CLOSET GROW FOR VEG .5) Do you have an exhaust fan and a circulation fan? NO EXHAUST, YES CIRCULATING FAN .6) What are the bulb wattages, kelvin ratings, and schedule? UNSURE Rating: 5