What are these Weird splotches on leaves!! Dying! (PICS)

Hey Everyone I have three Plants about 3 and a half weeks old. On one of my plants I first noticed what started out as dark brown or red spots on some of my leaves, these spots eventually turned a bit lighter in color. These leaves are slowly dying and I am also getting the same kind of spots on my new leaves. I dont think its nute burn because i have not given them any nutes yet. I have pics of the leaves. I accidently underwatered the plant one day and a few days after that it seems like it got worse. Im not sure whats going on. Does anybody know what this could be? Do they need nutes? Any help would be appreciated. This plant has been in Fox farm for about 2 and a half weeks.

First Grow so I know I am gonna make mistakes.. just gotta learn from them.

Soil: Fox Farm Ocean Forest
One Gallon pots
24/0 Light: 4 13 Watt CFL Daylight
4 26 Watt CFL Daylight
Watering Once every two or three days with half distilled and half tap that I let sit out for a couple of days.

I also have an Oscillating fan going 24 hours to ventilate the area.

What is your pH run off? It could be a Def, or your pH is swinging tomuch. I do believe with using Fox Farm, you dont need nutes in the first few weeks atleast not nitrogen fertilizers, might want to double check that tho. Like i said check the run off pH and your PPM if you can. Also judge your watering by weight, atleast that is how i was taught and how ive always done it. Might take a little while to judge but check the weight of the pot every day and gauge it from there. You'll know when its needing water if you can remember how heavy it was when you watered it a day or so before.
One last thing, take a picture of the entire plant including pot and then get a close up of the newer leaf with issues.

Start here:
http://forum.grassci...ency-table.html

possibly this, but plants are young
http://forum.grassci...deficiency.html

But will go with this:
http://forum.grassci...er-feeding.html

Your soil may be to rich in nutes for these young plants, next time plant them in seedling mix first and take a ph test to be sure


peace
"V"

Okay thanks man that might be why because PH is just about the ONLY thing that I havent been monitoring. I know i should have purchased a PH meter but I didnt. My other two plants have slight yellowing but not near as bad this one. Where can I purchase a cheap meter? And would the test strips for aquariums work on soil?

And I did start the seedlings off in seed starter mix. I kept them in the seed starter for a good bit before transplanting them.