brown dying upper leaves

hi yall

yesterday i changed the rez and changed nutes to ionic bloom at ec 1.4 (day 8 of flowering)
also done a light flush.
today my ph had a rise to 6.4
now brought back to 5.9

im thinking this ph rise is the reason for the problem
can any off u fine ppl confirm this or could it be something else

with just the super close ups there, it almost looks like severe heat stress.
I'm guessing the top of the plant is closest to the light.
A 6.4 ph is perfectly acceptable, it's not ideal but it is acceptable, it's not causing that kind of dying off..

Mystik said:

with just the super close ups there, it almost looks like severe heat stress.
I'm guessing the top of the plant is closest to the light.
A 6.4 ph is perfectly acceptable, it's not ideal but it is acceptable, it's not causing that kind of dying off..

Click to expand...

hi mystic
the light is about 9-10" from the tops,
also done some LST to keep them down