Very pale and droopy seedlings, unsure of cause

Hey guys I wanted to start an attempt at a perpetual, so I popped some seeds that spend the days outside and then 12 hours under a 400watt HPS with my flowering plants. A couple of the seedlings have halted growth and paled considerably, not sure if they're a lost cause. The third healthy seedling has developed 2 more leave sets than these and they're falling behind, wanted to get some opinions on what the issue/solution could be. At first I thought it was just overwatering but I've let them go dry for days and it doesn't seem to be helping.

From what I can see in the pics they don't look too bad to me, light may be a bit much at this stage of growth, Try switching to 18/6 to give them a rest.