Some seedlings are green, some are yellowing; Why?

Dear friends,
Hello all, it's good to be back. Some of you may remember me from my first grow a couple of months ago that was unfortunately affected by the appearance of a hermie. I had started with10 Shiva Shanti seeds from Amsterdam; all germinated and after a month of vegetative conditions, all grew to six feet! (This was too long, I learned later.) After sexing, I was down to four. Or so I thought. One of them went Hermie, and pollinated the rest. I ended up with about four ounces of okay weed, and about 10,000 seeds.

This time, I am going the sea of green route. I started by germinating a couple of hundred seeds, then planted the best 72 in a Jiffy 7 Greenhouse. After fifteen days, I transplanted 30 of them into 6" square pots. I came up with an idea that others may like: I bought a couple of plastic under-bed storage units. They are each about 32" x 20" so 15 pots fit in each one, for a total of 30 in my 6' x 2' closet with a 400W MH bulb (I switch to HIS for flowering). The plastic storage units act like giant saucers. After the initial watering, there was a pretty good puddle in each , and I planned on removing water by drilling a hole in the bottom of each and plugging it. But the puddles evaporated by the second day. I am not sure at this point whether I need the drain holes. You can see the set-up in the pictures I posted .
It's now day three of vegetation, and for some reason, some of the plants are yellowing. About half were transplanted into Miracle-Gro potting soil and the other half in a similar product from Scott's. The Scott's is, out of the bag, darker and moister than the Miracle-Gro. There is not an exact correlation, but it seems a majority of the seedlings in the Scott's are yellowing more than the seedlings in the Miracle Gro. (See pictures).
Anybody have any ideas why this is happening, and what I can do about it?

it looks like you are experiencing a deficiancy maybe due to a lockout in nutes? what is your ph? try to keep it between 6.5 and 6.8, if you have not fed any nutes start out with a very small light schedule of them goodl uck

Hey Vanayakananda ,,,,, it looks like the yellowing seedlings are ready for some "very" diluted food......good luck with that :^)

scotts ang MG are the same company bro. also was it plain soil or soil with slow release? ive seen Mg kill alot of plants

Thanks, dudes.

I have to say, weed smokers and growers have to be the nicest people around. If there is a greater hypocrisy than the marijuana laws, I can't think of it. Millions of half-conscious idiots can walk in to a store and buy alcohol even though it results in billions in unnecessary health care expenses and 30,000 are murdered on our roads from drunks, but we have to sweat going to jail for growing a few plants for our personal use. The marijuana plant is such a beautiful, miraculous thing, I think I would enjoy growing it even if I didn't smoke it. And as opposed to the mind-numbing effects of alcohol, marijuana makes people peaceful and insightful. Plus, it makes watching movies better, going to an amusement park more fun, and let's not forget, what's better than fucking with a nice buzz? (As opposed to alcohol, which makes it an effort just to get your dick hard).

I know, I know, I'm preaching to the choir, and I'm totally off-topic. I just had to get that off my chest.

The subject at hand: I had perfect success transplanting from Jiffy pots into MG last time (my problems came later), and looking at the crop, it seems the problem is pretty much with the ones in the Scott's. There isn't any other explanation I can think of. The soil tests at about 7.0 with the MG, over that with the Scotts. That's with using two different brands of testers, but they are the cheap, 3 in 1 testers that cost around 10-12 bucks, I still have a couple dozen viable seedlings still in the Jiffy pots; I think I will dump the yellowing plants and repot the remaining seedlings in fresh Miracle-Gro while I still can.

As for the questionable Ph, I need to add sulphur, is that correct??

Thanks again, you guys ARE THE BEST!!

i wouldnt add sulfur, look for something call sodium bisulfate, that will lower ph, u can pikc it up at your local pool/spa store or maybe even wal mart, 7.0 and up is to high that could be your problem friend i hope this helps good luck