New Grower and Damping off

Germinated my seeds in rockwool. In Brazil it is pretty hot and humid already so i just kept the rockwool wet. all seeds germinated but only 4 out of the 8 came up for air. after they did, i put them under a 50w led lamp before transplating to bigger buckets. i set up a system to flood and drain all the buckets from and to a reservouir. i didnt give my plants any nutes, gave them some root stuff 7 days after they popped up. so, 3 days ago i noticed a brown spot in one of the seedlings. right at the base of the stem. so i did a lot of research and it seems like it could be damping off. altough is kinda of dry and not thining. so i did a little hidroperoxide diluted mix and gave it to them. i finally saw some growth after days of being stumped. the brown spot grew and spread to all four plants. today i picked up some cinnamon and put some on the cubes. can you guys help me out? is it really damping off? cause they are not falling down… i didnt notive the leaves are getting lighter on the edges, they are halft a dark green, half a lighter green. i didnt want to transplant them to the big buckets cause i tought they were going to die, but 3 days later they are strong and still not thining. im so confused!

what should i do now? should i tranfer them? give them more light? i have a 600w led…

i think i did do somethings wrong.
i touched the roots, if the roots burst out of the rockwool they were exposed to light, my fan is blowing on them but its stationary, i dont have an exaust on yet cause that is where the big buckets are, and im pretty sure i overwatered them. lol

i did buy a container just to sprout seeds in case i did a new batch. i would be a DWC bucket. i got an air pump and 4 air stones. i have rockwool and expanded clay to play with, please help!?