HELP problem with my babys leaves yellow and shriveling up

these are the worst ones.They are 3 weeks into veg,are in coco they have only had 1 fed with nutes canna A+B and rizo,cannazime low EC 0.4 and that was 2 waterings ago so i dont think its nute burn? teps are good,they are under 1 200w clf and 1 250w cfl(450w) just now and at 47% humidity.any help much appreciated

all good it all my falt watering 2 days in a roe what a nugget (bad dad ha)