Yikes !!! Newest leaves ?burnt?

I've had ups and downs with this grow. Mainly leaves drooping then coming back ... today a new first..the newer leaves look burnt on tips.
All numbers are good pH, TDS, temp, RH%, etc. Plants roots partially in the water yesterday... above the water level today.

What do you consider good? Some strains will eat 10x less then others.but somethimes you just get a genetic retard that cant be helped...