why are my seedlings leaves curling at the tips and have a brown yellow color

the one in questioned sprouted the 27th right now two days away from one week old she looked fine until two days ago thats when the tips started to curl upwards and the tips look kinda brown in color i have it under a 23wcfl (100watt=to incandescent) its 5000k and 1600 lum it sits maybe four five inches from the top of the seedling its did have a problem getting its hard hat off but it finally popped a little late i have another plant under same conditions but its doing fine and its bag seed the one thats not doing so well is a kush the pics give a little description of what im talking about i know that is not normal for that to happen im new so sorry if im askin stupid questiones i want to learn and make sure im doing this right

Sometimes the sugar leafs do that to me to ,but as long as its growing it should be fine.

water schedule?
fan?
soil?

Forget any fertilization. Assuming that is not a factor.......

Keep temp 80F or below

Beyond that don't sweat it. MJ just wants to grow

Your taking about the cotyledons? If so don't worry about it. If your first true set of leafs look good everything is cool.

its growing okay other then that i water them only when they look like they need it i do keep a book log somewhere of when i do i use mircle gro for now if possible i would like to switch to a better medium for my veg and flower but ill get to that when times comes sometimes i spray a light mist over them but thats only been once or twice since they have sprouted my soil hold its water pretty well mycups do have drain holes for excess though my temp stays around eighty i figured goin any lower would possibly stunt growth(so it would be okay if my temp went below eighty but how low is too low?) my humidty stays at about forty five fifty the fan i use is a holmes blizzard i got from lowes right now its set on low its just a nice light breeze to keep things flowing moutned from a wall about two feet up from where plants sit its just now getting two more little leaves and its not the cotyledons(the two round leaves?) its my actual leaves that have the brown tips i checked them today it looks a litte worse not to much then yesterday they almost look burnt at the end but i dont see how anyone who has clfs know theres not that much heat and the heat it does give off the lights not close enough to harm the plant idk ive said before im not new to growing but i am new to doing it indoors its still cold a little where i am and i dont want to wait

btw i just use water forr now and whatever is in the soil no nutes not till im closer to veg anyway

i will add better pics in one sec