Quick One - browning on leaves

Hi @growinggrannie sorry for the lack of information on growing techniques Basically I am just growing them in shop bought compost (Westland Multipurpose Compost with John Innes) Not adding any nutrients at all The others are not showing this problem Lights are on 24 hours, temp about 21-24c, humidity 45-45% I have no way of accurately measuring pH or ppm/EC Maybe it's just this strain / this one

Your diary doesn't give us any information as to how you're growing them - your focus seems to be on the lights which doesn't have anything to do with what we're seeing in this plant. The very first thing I would tell you to do is to check your pH... something's off with it and is most likely the culprit here.... water her until you get some runoff and check the pH of the runoff... this will tell you what's actually going on inside the soil, the pH level that exists there... you can also check the ppm/EC of the runoff to add to your knowledge of what's going on with her. If it's badly out of whack (should sit between 6.2 and 6.4), you may have to do a flush on her to get her back to square one... and then figure out what nutes you were using and at what strength that you should either cut out or cut back on.... Understand that each plant is an individual and what works for one may not work for another... you're going to have to adjust your regimen (whatever it is - as I said, you don't tell us) to make HER happy... Good luck... but start filling out the diary a little more completely so we have the most information possible when issues arise! That helps us help you.

Thing is - the others are all fine - same watering - and I move the fan around in the tent regularly However she is a Quick One and the others the same age are White Widows

from first look excess of nitrogen , big overdry of pot at some time or consttant and wind damage on top. My guesses only, but i did more mistakes than any grower here, when i did the things i mentioned above - i had exact same look of plants, but it could be something other ....