Hey guys another question

A friend of mine has a few plants growing right now, Two in an approximately 4 by 4 cabinet with 3 75 watt flouros in it and another cabinet with one plant and 2 75 flouros. My question is the plant that is by itself has been through alot in its short life so far but i applied my greentumb and recently has been doing much better untill today I noticed these small light green spots appearing on its leaves. The other two are doing fine but i'm worried about this one. They were last fed two days ago and before that 2 weeks with a teaspoon of miracle gro 24-8-16 per gallon of water used, using a little less than 2 gallons for all 3 plants till the water ran out the bottom. Also of note is the fact that this particular plant was brought outside for a single day to gain some strength and make sure it wasn't over watered. Not sure if it has anything to do with it. They are a little over a month old.
Here is the one with the spots:

Here it is in its entirety:


Here are the two that are doing fine (Just to show them as healthy:



Any help would be appreciated, thanks guys.

those two bottom ones are exactly what mine look like...... do you know what strain it is??

haha nah, ive been trying to figure it out, they were bag seeds

looking a bit pale maybe nitrogen deficiency and i see a couple of leaves drooping which indicates slight overwatering

Get a good magnifying glass and look under the leaves to make sure its not spidermites. Spotted leaves are the first sign of the little bastards!

i agree but in this case maybe not the spots would be more evenly spread over the whole leaf but saying that you did say you put them outside for a day its a good job you got it isolated from the other 2

it wont hurt to give it a spray anyway

Yep, if you took that plant outside there is a chace that it got spider mites. That's why you should never take inside plants outside unless you are taking them out there to plant in the ground outside. Look at the underside of that leaf (with a magnifying device if you have one) to see if you can see little brown/black specks, as small as specks of pepper. They could be slowly moving around and will move if you poke at them. The bugs are usually on the underside of the leaf, while the damage they do can be seen on the tops of the leaf, it looks similar to what your pic looks like. Although it doesn't look like textbook spider mite damage, like coaster123 said, it is worth it to look and catch the little fuckers as early as you can if you've got them!