What fans?

Hello fellow growers I now need to know which fans to buy. The flowering room is a triangle shape ruffly 3m x 3m x3m and 1.2m deep. The 600w is going to be inside of a blockbuster hood and there will be under 10m of ducting in total (Mostly straight on outsides of tent).
I plan to run a 4" intake fan aswell as 6" exhaust, all through acoustic ducting and with the dual fan speed controller. This is a loft grow with the intake taken from the 4" bathroom ceiling fan (ceiling fan is not the intake fan, this is for stealth reasons only).

I need this setup to be quiet. Which intake and exhaust fans do I need? The loft has been treated with double foil thermawrap, and my grow tent for flowering is constructed from the same material.

Carbon filter/Blockbuster/ 6" Exhaust............4" Intake.

Reading your FAQ suggests that I should allow 330cfm3 for the 600w. I have however looked at the 550cfm3 iso box fan for exhaust and then wondering about the intake fan. Is the 550cfm3 a good idea to use along side a 4" intake or what would you suggest ?

I don't want to spend more than I need, but I need it to be quiet and I need adequate cooling during summer.

The thermawrap bubble foil insulation is in place under the rafters (overlapped and taped sealed)to deflect heat from the sun in summer, to keep temps up in winter, and to disguise the grow from Infrared cameras. If this extra info helps.

I plan to diffuse the heat within the loft space during winter, and to vent outside during summer.

Thanks.

Can anyone out there help ?

ummm, something ain't right in your logic dude. Why do you need an intake if your using an in-line carbon filter? The carbon filter IS your intake in the system you described above. Any decent 6" fan will work for you.

Don't reduce your duct down to 4". There is a massive loss of flow capacity and if you want to go stealth, your going to need the largest duct possible to maintain adequate flow when reducing RPM with the speed controller.

Hi, it's not an inline carbon filter but my aircooled hood will be sucking air through it on one end, and the other end of the hood will run to the exhaust fan. The carbon filter will be mounted in the peak of the tent, the inlet will be in the side of the tent at the bottom.

The exhaust ducting out of the top through carbon filter and light is 6" and the intake ducting into bottom of tent is 4"

Thanks