First time grower need help

I have recently decided to have a crack at growing again(first time was hydro) ive decided to grow purple kush auto, skywalker kush, kosher kush,berry bomb, sour kush and sour diesel in a 4x4 tent one 600w hps bulb in 11gallon pots they are now 24 days old from seed but am starting to have problems with most of them what am I doin wrong. oh I am using canna A and B nutriates as well as canna coco professional plus.over the Pass week and a half say the have like green colouring on the leaves and the sour diesel has glossy top fan leaves with brown or a dark purples edges trying to upload picture. They also have a lil pause in growth for a day or two then resume growing