seedling issue. plz look

so here's the background:
shes about a week old in MG soil (which will be changed to FFOF on manday)
but her leaves have started to drop a little a some brown spots have appeared.
i have only given it water and the ph stays between 6.2 & 7.1
shes under 600w HPS
any ideas guys

(I DIDNT MEAN TO ADD THE 2ND PIC AT THE BOTTOM, JUST DISREGARD THAT PIC, THATS MY OTHER GIRL)

may be too much light for the seedling. heat stress? if u repot it will stress that baby out bigtime. i recently repotted my 6 week olds and they took a week to recover. i have no probs with mg. not sure u can buy ff in canada

600w is way too much for a seedling - try using CFL's for the first 2 weeks. Also, seedlings shouldn't be given nutes - because you are using MG soil, everytime you water your soil nutes are being released.