Someone please, HELP my clones are dying

I have them in a homemade aero setup. I started them last tuesday, and have been misting daily. Within the last 2 days the bottom leaves are turning yellow and shrivering up. Is there anything that I can do or are they done?

is it just the bottom leaves? Everything else looks good?

the clones should be coverd with some sort of plasitc coevering for humidity,
are the clones rooted?

No they have not rooted yet... And yes it's just the bottom leaves though the top ones look like they are ready to go also. I will add pics lata.