Strange things going on with my mr. nice and dynomite. Any Thoughts?

Been vegging these for a while under t5's. The golden/light green spots on The dynomite leaves started popping up a few days ago. Same with the mr nice dying leaf tips. And it seems like there is a lot of leaves dying on the very bottom of some of the plants. I know some is normal but i know somethings up with these plants.
Over Fert? Im using Age Old 12-6-6 (last feeding i might have overdone it a bit).. (i also have pretty bad ventilation) Temp 80 hum.50-80
I mean their all pretty healthy, but their going outside very soon, and i wanna be on top of it before they go out.
Thanks ALL

O, also i use cal/mag 0-0-2 along with the Age Old Grow

hey bud im no expert and have only got a few grows under my belt but does your grow room get damp. when lights are switched off and theres no air flow into the grow room at night this can happen. Hot temps mean the air holds much more water and when lights go out all that water drops out of the "sky" onto the plants. It happened to me not so long back..i switched everything off in an emergancy and shut the grow room door..fuck man they were soaking wet.

if thats not a problem do you think you could have over watered them. The leaf in pic5 looks like its got wet and is dying off. And the spots on the other leafs look like they might have been feed too much nute. Like I said this im a newbie(ish) so this is just guess work. hopefully someone will have a better answer or you get it sussed. good luck mate