My first Crop, Journal 1.

dude i would sy set up a fan, airflow is really nice for makin them trunks get an excercise and they get a lot stronger, i hope you got some intake air and exhuasting air, i would hate to c them babies growin up in stank air

Word, I'm thinking the same thing. I was thinking of setting two up. One on top above the lights blowing gently downward, and then a second small fan by the plants, blowing it out the closet. You think that's proper?

how big a closet you got ?

Height is about 8ft, length is about 4.5 ft, and width is about 1.5-2ft.

it does sound proper, have a fan blowing inbetween the plants and the light, it gets rid of heat that we dont want. the fan you blow on the plants shouldnt be set on high, dont trash the babies, i prefer i lil shudder from them every now and then, you know the air is fuckin with its stem if the plant is movin from the forced air. all i got is a 3 speed box fan macgyvered by two shoelaces above my lights in my 3x3veg closet, i have it blowing downward and it seems just fine, they shudder nice, and i have 10 48" t8's in there so heat isnt so bad, there is still fuckin heat but it would be worse if you had a bigger setup like you, i had a 600hps/mh in a cool tube hood in there before this, it was hooked up to a 440cfm inline fan , it was still hot so i feel ya..... but yea, give dem da wind brother

you just want an oscillating fan blowing on the plants, if you have a fan constantly blowing on the plants they will waste energy building stronger stems than you want. one oscillating fan blowing on the plants and a single exhaust fan (with a carbon filter if you don't want smell) will do just fine for what you have. the yellow on the leaves you spoke of could be nutrient burn. 36 inches might be a little far, keep the light as close as you can without burning the leaves. (hold your hand under the light, if its too hot for your hand then its too hot for your plants) i keep my 1000W HPS about 1.5-2 feet away (maybe a little farther during flowering to keep the buds from getting too hot)
also Fox farm big bloom? I havent used this but isnt this a nutrient you use more during flowering? not for vegging? help me on this one

with that size room a 4 inch inline exhaust fan with a passive intake will be enough to exchange the air

you could just have an exhuafan going out of the room if the room is airtight, then once you turn that fan on it can suck in fresh air, make the surface area of your exhuast vent about 1/2 the size of the surface area of your inlet vents... youll have to make some inlet vents if you wanna do this, unless the closet isnt airtight then it will exchange air anywho.... i still have the 440cfm inline fan suckin out the warm air from the veg closet , it is light tight, but there are a few spots where new air can come in.......