Newly sprouted yellow spot

Hey guys. First time grow and im watching my babies like a mother with a newborn. 4/5 seeds sprouted the day after planting. one i think may be dead but im leaving it in my closet for a few more days to see if it pulls through.
However one of my sprouted seedlings have a small yellow spot on one of its leaves. Im just a little worried and wondering if you could help me out.
3 days before i planted the seeds i poured a little root strengthener and veg nutes through the soil and allowed it to mostly dry out. Since planting seeds i have been watering 5-6 times a day but only enough to dampen the topsoil a little. I done this with a spray bottle that gives a mist type spray so i dont think im overwatering by doing this. just keeping the soil moist.
Anyway here is my sprout. Its difficult to see properly in this picture
Is my plant healthy?

looks fine to me man, its natural to worry about every little thing that you see most new growers do, but what you gotta realise is these plants spent millions of years evolving to survive and are actually quite difficult to kill. dont keep the soil moist it isnt a swamp plant, it needs to dig its roots deep into the soil looking for moisture to develop a strong healthy root system and the roots need to be able to breather it is very possible to drown your plant watering as much as you are. Best results come from letting your soil dry out nearly completely and then waterign thouroughly. Not sure what your setup is but my seedlings or new clones in 3 gallon pots under LED usually dont need to be watered for 2 weeks or so after i first plant and water them

alright cheers man. I have a 250w setup in a small closet. Now that they have sprouted would it be ok to change the light cycle? Since planting sunday ive had them under 24 hours of light just to keep the heat up a little. Im wondering if now is the time to switch to the 18/6 light cycle?
heres my setup. pretty fine for a first grow id say

yup you can go to 18/6 any time you feel like it, although there is no real reason to unless you are woried about power costs, plants will veg just fine under whatever light cycle you choose. I also recomend buying a moisture meter at your local hardware store they are about 5 bucks and are very reliable for telling you when to water

nah i calculated it to cost 60 euro for 2 months of a 24 hour light cycle. So thats not a concern. but ive read in a few forums that the plants like a little rest and they grow well with a short dark period. However ive also picked up on the fact that different growers have different strategies and preferences. So is there any real benefits or drawbacks on a full 24hr or using dark periods?
My setup at the moment is a 6 inch fan always on, 18/6 with the 250w light and an extractor fan that turns on for an hour then off for an hour repeated just to take some heat out.
also as you may have guessed i went with an autoflower. Caramella auto. http://en.seedfinder.eu/strain-info/Caramella_Auto/Expert_Seeds/
But i cant find any grow journals to use as guidelines

what light cycle to use is one of the more debated topics that comes up, personaly i belive the more intense the light source during the day the long the night period needs to be, my theory on this is based on the face that there is only so much light a plant can use during the course of a day. A 250w HPS is a relativly small light source so id say it'd be fine on a 20/4 light cycle. I personally run 600w of LED over 4 plants which is pretty high wattage per plant so i run a 18/6 light cycle, if i was usig a low intensity light source like CFL id go 24/0. Autoflowers defintly do need a dark period to get best bud deveopment so 20/4 would be my recomendation

Alright. Sounds good to me. Thanks for your help man. I would add more rep if i could