Any Idea ? mn or mg or need more nutes?

Any Idea ? why leaves doing that have anyone have this iussie?
room temp 75
water temp 67
humidy 43
ph stay at 5.6 to 5.9
eeb flood table with hydroton in pot .
ppm 900 dropped to 750 the next day .

any idea plz ?

Maybe the light is too close.

well they are about 26 inches away .