n00b question: same medium, same conditions... wildly different results

hey guys, this is my first post after reading the forum for months preparing for my first closet grow. here's where I'm at so far:

I'm starting seedlings in a bevy of different ways and most are completely failing, but one interesting trial is a seed starting kit made by a company called burpee. they have ten small discs of an unknown substance which you expand with water. I placed ten seeds in and waited.

today is day five of 24 hours light (2 32w 2700k warm white, 2 27w daylight; with reflectors). here's what's happening so far:


this one looks strong and healthy

but the only other potential strong one at this junction looks like this


I don't know if it's obvious but there's a brown spot on the underside of this one.

is there something going on that I am missing?

here's a photo of how it's set up, I've been rotating it twice a day.


any and all help, suggestions and opinions are welcome! I'm happy I finally joined the community!

you should put those seedling alot closer. they are gonna stretch really bad otherwise. its only been 5 days, they look fine, sometimes it takes a lil bit for them to really get going strong. in 2 weeks they should be pretty big and healthy.

thanks for the reassurance. I guess the ultimate reason was the seeds viability and verility. this morning when I checked, the burnt one had opened up and grown two new leaves, in only 8 hours! I can't wait to get home and check on them.

also I put a book under the starting tray, let's see what some closer light does to them. If I did want to induce a little stretching then I will move them later, I have 10 feet of height to work with and basically unlimited access to bulbs, cords and splitters.