edge burning normal or??

So the stems are long due to a one day marthon sprout that I didnt catch, but other than that looking really healthy until yesterday when I started to notice that the edge of the leaves *toward the bottom* are starting to burn? die? My pH is a steady 6.8 and I am watering with a 1/10,000 mix of fert every four days or so. I give them a spritz every two days. Any suggestions on how to improve the growth and to stop the tip burning?

any hints are much appreciated.

Cheers

looks like a very slight nitrogen burn. but i scanned your fingerprint, so you might have a few other things to worry about. knock, knock, knock.... who is it?

My thoughts exactly. Hit the grow store for a large order with moms credit card next. lol