Seedling brown spots

[Thcalec]

So I have about 33 seedlings about 2 weeks old in a 10x10 tent great ventilation and temp between 74-79 degrees and one of them have appeared some brown spots on the lower first set of leaves and was just wondering what your guys tho ugh they it could be

 

[SPARECHANGE]

ppm/ec
ph
of medium

it's nothing to chase, being first leaves and the only anomaly, but u can double check the values in the medium. it's not uncommon and she may just b a more temperamental pheno. they'll b the first, besides celotydons, to cannibalize. they don't need much, if anything, at this point, but that ones hungry, early.
if you're givin em nutes, by hand, if u splash, that can happen.
if u water with lights on n splash- sunburn.
just check its values n keep an eye on it. the rest r fine- it's probably fine.