dying seedlings(Gelato 45 barneys farm)

Putting a humidity dome like the bottles i see in your video will certainly help to kill your seedlings. Get it off of them slowly and carefully over the course of many days. If you have a dome on a seedling and where the humidity within is close to 100% and you remove the dome and expose them to a immediate and drastic reduction in humidity. You can lite up and joint and sit there and enjoy watching them literally die before your eyes. Stop misting your seedlings. You are using a 600w HPS over seedlings. That is so overkill it's not even funny. You don't need that much light to get those girls started. A fluorescent light is plenty. Your using way more electricity than you need too. H.I.D lights will dry out your air quite efficiently as well. and produce a lot of heat. If you insist on using a HPS then it better be WAY above those seedlings. Too much light will fuck them up. Too low humidity will fuck them up. Excess wind will fuck them up. They are tender and fragile man. They are babies. They look very leggy and stretched which indicates your light is too far away though. I dunno only you can know that i can't without seeing it. I think it's too hot and dry for them, but you've not given any environmental info so i have no idea other than my best guess based on seeing what they are doing. Your temps in there should be around 80F and your humidity should be in the 65% neighbourhood.