Seedlings with yellow spots

These seedlings are about 3 weeks old; I have been testing the PH every time I water them. I am using Supernatural brand Gro Terra nutrients. Because the soil has some nutrients in it all ready (about a 2 week supply) I have only give the plants a small dose of the nutrients that I mentioned above. As you can see from the pictures I posted these plants have discolorations on the leaves, if anyone has any information about what the problem might be let me know.

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Update: These plants are from seeds to now about 3 weeks old. They started in seed starter plugs and about a week ago they were put into these 1 gal pots.
I wattered them when I put them in the 1 gal pots and I have not wattered them again as of yet because the soil has stayed damp, and the root systems probable are not big enough to take in all of the water.

Id stop useing the extra nutes, flush well. test your run off and see what ph you get.
but i would stop useing the extra. do they have a good rooting system yet???
you might wanna trans plant early to help get rid of that soil fert.
i dont think that its a trace element problem but you might wanna look at um.
good luck

dude, flush immediately, for what i understood...if your soil comes with nutes, you're not supposed to feed them anything until 3 week. your plant looks stunt, probably the amount of nutes in the soil...your plant should be bigger than that after 3 weeks.