curling down and burnt tips.. possibly nutrient overabundance of some sort.. but, don't dial back too much in flower. Plants are more sensitive and show this sort of thing more often in bloom than in vege...
difficult to know what it is for certain.
However, when i look at diary, i see a lot of yellow leaves near bottom -- can be normal with a thick canopy. But, that's a sign of a deficiency of a mobil nutrient.
Work out your ppms of what you have feed consistently and make an educated guess.. don't just do something without some elbow grease invested into effort. definitely don't do what some random person says on the internet :P