why wont it unyellow

i added nuets my other sproutlings are taking it well and begging their next set from their first 4 and my one that got yellow bad some of it turned a light brown anyone know why?

could be heat stress, nute burn, humidity problems, or anything.
get some pics bish! LOL

i dont have cord for it lol nor money for cord but as soon as i can i will the tempature stays between 70 and 80 i added 2 small scoops of mircale gro and they were doing great and so if it dies its ok but it has 6 more leaves coming in but the one bit of leaves that turned yellow from no nutes i just thing they were to withered to recover even with nuets but the other 4 are doing ok except on that was defective so i now have 3 begging the cycle of its next leaves with 1 scoop for every 3 gallons i put 2 and 1/2 smal scoops in when they beggin to wither on tips and from their i now have 3 100w equivlents on them since one was deffective i took the 4th light out but other than that this week i am getting some more seeds hopefully thanks for the advice pwizzle and got any advice on fast aggresive growth strains that u know uv if u do thank for the help