yellowing on seedlings?

they are less than two weeks old, under 80 degrees, have decent moisture (i manually mist it with a mist pump), using tap water to water, im only using a 27 watt cfl but i figure it would suffice for the time being, yes i have a fan running but no method of Co2. can you please tell me what possibilities of the yellowing could be?

It can't be seen in the picture but the leaf is almost bright yellow, more yellow than visible

my guess is your overwatering , thats a noobs number 1 problem "no joke" it happend to me when i started out. does your soil have ferts in it ? like a 6 month feed? if u need more help pm me. u should only be watering every 4-6 days. depending on pot size and wind and size of plant.

it's a really small pot, like the height of someones palm? i stick my finger down towards the bottom and wait till it's almost bone dry but not completely, it's really small and becomes dry 12-16 hours of watering,


Update. The tip is wrinkling, it looks like it's getting really fucking dry...but only on one of the starter leaves, i figure they're gonna fall of anyways, should i just not worry about it?