Yellow/limp first true leaves

Hello, first time grower here.

I'm growing in FFOF, 4 plants(Starburst Bubba FEM)
Using some spring water with seaweed extract(Maxicrop 1Tbsp per gallon) PH'd to 6.8
600W aircooled MH lamp Ballast running at 75%
Temps in my 4x4x6.5 are 77-79 degrees.


Plants are about 2 1/2 weeks old from first sprout, all look great except my bigger one. The first set of true leaves seem to have turned yellow with some other dark(ish) spots. The rest of the plant looks great and they are about to get transplanted in to 5 Gal smart pots in to FFOF soil(might add some dolomite lime). Wasn't sure if this was normal or maybe something is wrong.

Thanks for all the help, sorry if this is a lame question.

~Kbear

OF will feed for at least a month. Anything else added could nute burn. Youre giving it too much stuff

Okay, thanks for the response!

Looks like maybe just too much water, with the yellowing from the bottom.