exhaust fan ?

need advice on a new fan , the room is 5 x 8 , i may use a 600 hps or some led, i no the heat will be very different on the 2 lights so , i want a fan that will work for the worst case. the distance will be about 30 feet of 6" duct to reach my vent with 2 90 degree bends , so im sure ill need a large cfm fan ,
any thoughts on a fan that will work and be somewhat stealth !!! quiet , what are some of the most quiet fans???? vortex ? and what size , thanks

You need to figure out how many cubic feet are in the space that you want to exhaust. Your space is 5'x8' that is 40 sq ft. So for every foot of height add 40 to find out your cubic space. Take into account the 30' of ducting the air will flow through as well.

Example: if your space is 8' in height you have 320 cubic feet. With a six inch 400 cfm inline fan, you should be ok.

There are many ways to dampen the sound of a fan, build a box with insulation, place your fan away from the space and people, wrap your blower in insulation, you need to find what works for you.

And the best way to battle temps is with fresh new air, especially air conditioned air. Find a way to get new fresh outside air into your grow space and temps won't be as hard to battle.