Plant Yellowing-- HELP!

This is our first grow, and things have been going good except for the yellowing we have been getting on some leaves. This problem does not effect all the plants and has been happening since the week after planting. It only effects the tips/ 2nd 1/2 of the leaves and really only the bottom ones. I'll explain everything we've done and HOPEFULLY someone can help us.

We germinated 3 weeks ago using a paper towel/water/mason jar.
We planted first into plastic cups using Miracle Gro Organic Choice Soil.
We have flourscent lights on our system right now. Each ballast has a cool white and a warm white in it. We'll move to a HPS during flowering.
We use water that has been sitting out for a few days to remove the chlorine.
**The problem began before we ever transplanted or fertilized**
We transplanted into bigger pots (1 gallon) at 11 days after planting into the cups.
We bought Jack's Classic 20-20-20 fertilizer and used it for the first time on the day that we transplanted.


PLEASE HELP US! Here are pictures of our set up, and the problem!

Also...how often should we fertilize & spray the leaves with a water bottle?

the black tip makes me think nute burn but im not sure

Not all of my pictures uploaded....so here's some more.

my guess would be that you over fed them with the nutes.

those look a lil young to feed, how old?

They are 15 days old. We saw the spots & yellowing more before we feed them at 11 days. If anything the nutes (1/4 strength Jack's) is help. I really doubt its the nutes.

Our current theory is maybe a mg deft or some weird issue with out water.

Are there any types of bottled water which work?

i have a similar prob using jacks too, except i dont have the "nute burn" look your little plant does, mine doesnt look burned on the edges, mayb too much fertilizer?? (not trying to jack thread)
my problem: https://www.rollitup.org/marijuana-plant-problems/329410-yellowing-plant.html