thoughts on air extraction

I am growing in a 1/1/2.5 M room .

Should I run my 400 CFM exhaust only through my cool tube?

Or should I run a Y connector/splitter - one to my cooltube
- one at the top of my room

I am trying to make sure not to have any heat problem from my 400 W

I think you are fine all in one

leave one end of the cooltube open it solves the issue of cooling your light and sucking hot air out your room/tent

well, that's what I'm gonna do than !

thanks for the answers !