Yellowing seedling leaves?

So my friend sent me a pic of his seedlings and he has about 6 and they all seem to start yellowing. Looks like a deficiency or overwatering? I helped him plant the seeds by giving him some of my soil. I mixed it with 3/4 of Black Gold Potting Soil on the top and 1/4 OF HF on the bottom. I dont think seedling leaves would be able to use up all the nutes in 2 weeks.

Dark green leaves, light edges; that’s nute burn. Looks like the roots have reached the OF soil.

Just a little too much nutrients but nothing to be alarmed about yet. Since the nutes are in the soil, pretty much just gotta let it ride until transplant, which will be soon by the looks anyway.

Little bit of overwatering too, which is why they are taking up extra nutes.