Are you in soil? If so you should not be feeding yet. Big bloom should be fine but grow big is real potent, it will kill a seedling. Looks overwatered as well.
mother earth coco & perlite
I don’t grow in coco, let me tag @MattyBear so you can get his input.
ok and if over watered should i change it into a new cup of coco & perlite
What are you ph-ing your water at?
And do you have good drainage in the cup?
Nah, just let it dry out for a day or so…
Idk much about coco bit I think it’s typically a “flood and drain” but I really don’t know much about coco my freind 
Sorry
between 5.5 and 6.5
Welcome BTW sry mate just realized you was new 
I wish I could be of more help but I don’t know coco.
It looks like nutrient toxicity to me but I’m not an expert so we let someone else judge.
Ph needs to be between 5.6-6 with your target number at 5.8-9. Do you have proper drainage in the bottom of the cups?
yes i do about 5 holes
Let it dry out for a day and then feed at the proper ph to runoff. Do you have a ppm/EC meter and a ph meter?
And do you have the feed schedule for the Fox Farm nutrients?
At the right tds conversion 500 /700 scale
Thats ur problem you have fed ur plant nutrients when its to young i would water it with plain water ph at 6.5 for awhile ,if u do give ur seedling nutrients use a ml of liquid kelp fertilizer in one ltr of ph water
They’re in coco
Coco needs nutrients from the get go and also not ph’ed to 6.5
Definitely over watered. I would go ahead a replant it in a bigger pot, and don’t water for a while.