redoing grow room for summer

I'm going to be redoing my room for summer.Adding an AC and a 5'cool tube w/ a 1000 and a 600, the tube will be direct out to out vented. my concern is do i need to run the exhaust vent constantly?It seems that it would kill the AC to just be pulling all the cool air right out.or would exhaust on a 15/45 timer be better? what do you think?

maybe?....

i would just put the exhaust on a thermostat you can get from homedepot its for attics when it gets to hot it turns on.

get some pics up

pics will be up in about 2 weeks I'll start a journal. Got to wait for my flat garden to finish then in for construction