Little problem please help first time grower :(

Hi, well first of all im using coco soil, ph water 6.0-6.5, humidity 45-60, 2x 600 watt lights, temps 77-84F Only fed once but over fed but then i flushed here are the pics. I have 8 plants all together and the rest are ok for now I think, they are red diesel feminized seeds from barneys farm

Any help or feedback is much appreciated, i can also post pics of my grow room if that would help