need some help!! brown root tip?

wat up everybody! i planted my bag seed about a week ago (germinated and all) and it sprouted in about 4 days. it now has been 6 days and i notice that my stem is a reddish color, then goes to white below it and i see brown right before the stem enters the rockwool cube. and this part is very skinny. also there is a slight brown on the tip, but i got the cube resting on some hydroton rocks, should i be putting the cube in the rocks right now? and the stem is leaning... i think im just going to get a tooth pick or somethin that can steadily hold it during the seedling stage... if you guys or girls can throw 2 cents in on this it would be greatly aaprreciated. thanks!
btw. im using a DWC/bubbler, cfls, and the lucas formula. no nutes yet tho!! just water for now and i have watered it like 3 times not even in 6 days because the rockwool is still damp. ill get some photos up!
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