Fast fix for this ???
Fastest way is Floral Spray with Cal/mag 1 hour before the lights turn on… Most Cal/mag have directions for it on the bottle for rates…
Or you can spray Epson salts
Just a FYI
The damaged yellow leafs will not come back…
But you also need to come up with the problem why this is happening… Is it Ph??
What is your run off Ec and Ph?