Clone Nutrient Deficiency?...

Anyone know what this is? She's a Afghan Kush x White Widow clone, the only one that rooted. Put her in a bubbler two weeks ago (with good roots) on 50% canna veg. All the other plants in the grow room are fine, Ph, temperature etc. But this strange browning of the edges started about five daze ago. Shall I flush and refresh nutrients...or what? Advice please..gratefully received..
(Oh yeh, I don't think it's nutrient burn; I've done that twice already! hahaaargh!)

it really looks like nute deficiency or light burn.. post a pic of your setup

i dont think youre burning them, i think its a lack of nutes.. after burning them, you could be going a bit too light on the nutes.

She's in a bubbler under 250 cfl (and other plants are in the same set up), and no problems there. Most likely a lack of nutrient I reckon. Should know better; I did this last time
I'll up the food and post how she goes...
Thanks for the help