is 250 CFM exhuast enough? 1000w MH Veg Room 6X3X8

Hello everyone. i have a Ventilation Question.
OK my room is 3ft Wide 6ft Long and 8ft High (6x3x8=144CF right?) so i guess what im asking is... will one 250CFM inline fan be sufficient enough to ventilate my room AND cool my 1000w cool tube? i want to have a single exhuast connected to a "Y" shaped Vent Duct (see attached pic) pulling air from the room AND the light together through a DIY carbon filter. should i add an intake fan also? (id rather not if possible because than i would have to "Y" the two intakes together too = more and more $) Thanx in advance for any and all comments.
happy growing.

i wouldnt use the Y duct because the air is going to go the route of least resistance and not cool your bulb. i have a similar setup, my room is 1/3rd the size with a 600w bulb and 500 cfm fan, i found that airflow wasnt as important as making sure that the intake air is cold and the exiting hot air goes somewhere where it cannot be recirculated into the system.

plus i think that if you add the Y then your are cutting the cfms that your bulb will see in half

With a room that size and 1kW you will need a much bigger fan.

maybe If you got a couple duct boosters inline with your 1k cooltube. I think you would still need more than 250cfm though

Nice diagram, i think i would put the good fan before the cool tube and push cool air though it and get a cheap home depot fan that you can mount right on the other side of that y pipe. They also sell a duct stat for 24.00 that would make the cheap fan turn on when the room got to a certain temp, like 78f it would kick on. if it is a real cooltube they are supposed to be very good at removing heat fast with minimal cfm fans.

nice thank every one for the replies. i think u guys are right one fan using a y will not be enough.
i went ahead and bought another fan same size 6 inch inline fan 250cfm. i believe it is designed for boosting duct air, it says something on the box about the stat u mentioned sixstring2112. so would this be enough. i had thought of putting them both as exhaust and pull the air. one for the cooltube pulling thru passive from a/c coolled room and the other pulling air from the room also passive air from an a/c cooled room. i had not thought about putting it before the light to push air. hmmm i will consider this. would this be more effective? do i than pull air from room and push air into light? where do i put the fan? at the opening of the intake vent to grab the cold air, (see A). or up in the tube in front of the light to push the air thru? (see B) i do think wiring the fan to run at spot B would be difficult though

hard to tell cause you have a room that is temp controlled connected it should be okay but really to be honest it likely wont be enough

what about with a 3x3 400w setup grow tent with a fan blowing in a passive intake, and sucking out the other side up into the attic.tested it out, put a lighter up the intake and turned on the fan, sucked the flame down pretty good, and the outside room being temperature controlled. you think a 250 cfm fan would be suffienct for that?