need little help

i can not figure out whats going on with these two baby plants .... there 11 days old there northern lights / bubbleicious .... under 600w hid but i got it 2 feet away exact thinking maybe heat stress .... there in i think 5gal buckets with ocean n forest / happy frog mix the one plant is curing up / edges turning brown other over night started curl up then other 2 i got are fine ph them 6.5 have fan in the tent to keep air moving lightly

Maybe your soils too hot? What's the ratio it's mixed at?

Also what's the temps at?