Yellowing leaves in seedling stage

Hello guys!!!

My seedlings inner leaves has started to become light green/yellow and if you look closely on the picture you can see that the tips of the smaller leaves look burnt. I have a 600w MH lamp with cooltube and I raised it 10cm yesterday to be around 50cm from the plant.
I made a mistake and transplanted my seedling too early into bigger pots and the growth has been slow since germination (pic was taken 16 days after sprouted).

I have a problem understanding when the seedling phase ends and when you should start feeding nutrients for the vegetative stage.
Yesterday I gave the plant 50% of recommended nutrient dose to see if the yellowing is because it is time to start feeding.

Could someone help me solve this issue with the yellowing leaves?

light way to close i think bleachin the clorophyl out of it.
done this many times haha
although i can see tiny bit of burn on inner leaves?
what medium you in and its to early for nutes yet that soil will provide while still that size.

u can have to intense light without the heat present beleive or not lol

I think I am have the same problem. put a 400 watt led about 8" away is this to close and now the new leaves are turning a little brown and some almost black. is it best to use cfl's through veg. or for the first couple weeks? should I just keep the led further away?

I am using Bio Bizz light mix soil. I have raised the lamp and I believe it is within the right distance for the moment. I attach two new pictures that were taken yesterday. Are the three fingered leaves the second set of leaves in total? In that case, could somebody explain when the start of the vegetative period is?

I waited to water until the pot got dry and the yellowing slowly dissapeared. Things are looking fine now with the colour of the leaves but I have another issue now with some leaves having holes.. looks like some bug took a snack or am I wrong? Do you recognise this or have any idea what it can be?

in my opinion you're feeding your plants way too soon. you should hold off on the nutrients till you see at least 2 fully grown nodes of growth. for seedlings your base soil should have enough nutrients in it to survive and grow, i usually give it pure water till the 2nd week. Your last picture shows exactly the right time to start feeding nutes. The soil you are using right now is good for your seedlings, you didn't need to feed them anything.

are you checking your ph in your waterings?
where is your water coming from?
was your seedlings that yellow since it sprouted, or did it turn that color when you fed it the nutes?

And for your " holes ", not sure if something bit it off, or it's deformed growth. Deformed growth can be cause by overfeeding and ph. Bio has enough nutes in it to let the seedlings survive when you fed it nutes it made the soil even stronger which im guessing that's what caused you problems. That bio light mix is meant for seedlings, goodluck man.