Your lights are fine, but something is WRONG!!!! lol. Your plant looks like mine when I repotted it after being in the windowsill for three weeks, and being heavily flushed.... It had poor drainage... Are you letting them dry out completely before watering? It may be dampening off from watering too much. Or your soil could be very thick and hard to dry, therefore keeping your babies roots wet. Your temps and lights are fine. LAY off the water but when you do: Water with room temp water...and make sure the ph is okay. B