My Newbies Are Dying

My babies are dying off. They are only 3 days old under flourecent lighting. I germinated them in rapid rooters. Today I found 2 of them dead. The stalks rotted away just below the dirt surface and there's only a small tap root no other root structure. I've only watered them once and I'm using fox farm with bat gauno and worm castings with half perlite. I've always used rapid rooters and even recently tried peat pellets but experienced the same problem even more so. Does anyone know what's going on?

Maybe they are too damp, or the nutes are a bit to strong. how close is the flouro, and how powerful is it?