Worrying Problem(pic)

[sumbadazzbud]

Right i've got a lil worrying problem for the past few weeks leaves on my plants are turning a weird brownie yellow colour and are crisping my strain is ak47 I've no idea what this is but i'm close to prematurely cutting incase it effects the buds, I've 1 plant at 7weeks and 2 plants at 4weeks which this is effecting the symtoms appears to start at the centre or the tip of the leaf and slowly effects the whole leaf untill it wilts away i've been cutting the infected leafs off but this has not stopped it I thought it might be an overnute problem and so i cut down the dosage but didn't seem to stop it anyone with ideas or treatment?

Medium: Soil
Nute/Additives: Hesi Bloom, TNT ,Root Complex, PK 13/14 and Supervit Adminstered once per week
Lighting:600 Watt HPS

Tempreture stays at an average of 80 Degrees during lights on but drops to about 45 degrees during the night

EDIT: Oh one more thing, from what i can tell it only seems to effect the fan leaves especially on the 4week flower clone

 

[bucket o queens]

have you tried flushing the plant. usually i say the symptoms will go away after about a week. i'd say if its not affecting the buds it may be a mild nute problem and trim the dead matter away.

 

[heathaa]

in flowering especially after the 4th week after the plant is getting closer to harvest it is natural to loose your lower fan leaves and its possible to loose more as you get closer to harvest. i assume your about your 5th week. if you want you can trim the few dead leaves off and watch it everyday considering you only have a couple weeks left. good luck. flushing before time is a last resort. you dont want to flush the plant till about 1 or 2 weeks before harvest. that will get all the nutes out of the dirt and force the plant to use up stored energy which will help alot with taste. i have bud here im smoking that wasnt flushed and it tastes so crappy

 

[Sidewinder73]

in flowering especially after the 4th week after the plant is getting closer to harvest it is natural to loose your lower fan leaves and its possible to loose more as you get closer to harvest. i assume your about your 5th week. if you want you can trim the few dead leaves off and watch it everyday considering you only have a couple weeks left. good luck

Agreed, I wouldn't worry too much. Everything looks nice, but I do like to flush for a week or 2 before harvest.