Exhaust for 600 hps, 5ft x 9ft room

Hi again,

So I have 5ft x 9ft room(1.5m x 2.8m) where I plan to grow 4 plants under 600 HPS lamp. I know I can grow more in this space but I don't need to.

For this grow I need a really really quiet exhaust fan. After lots of reading I decided to go with a bigger more powerful fan like 880m3/h (518 cfm) and use it with speed controller because as I understood it will be more quiet that way than buy using 400m3/h fan at full speed.

Now, considering that the growing area is big but there will only be 4 plants under 600 watt HPS what size my carbon filter should be ? Should it be for that big fan I will buy or can I buy a smaller one ?

And will this idea of buying more powerful exhaust fan and running it with speed controller save my ass ?

Can someone please calm me down ?

I can just relate my experience:

Got this fan: http://www.amazon.com/gp/product/B002JQ14F8?psc=1&redirect=true&ref_=oh_aui_detailpage_o05_s00

W/This controller: http://www.amazon.com/gp/product/B003URBQ1M?psc=1&redirect=true&ref_=oh_aui_detailpage_o04_s00

Went with the Active Air controller because a couple generic controllers I had would not, well, uh "control" I guess. Speed varied sometimes, only full speed or off, etc, so went for the same mfgr controller w/fan and it works perfectly.

Anyway I run mine off a 5X6 foot grow space w/a 600 and close to 400 additional CFLs and an LED.

I only run it at maybe 30% speed and it takes out all the heat. The grow room is in unfinished basement that stays around 68f naturally.

The fan barely idles, and in my opinion, very quiet, but I am half deaf. As far as carbon filters I have no idea, never had to use one.

Anyway I think something along this line might serve you well for not too much $, I have four full grows with this one fan and a after a quick calculation I would say I easily have over 4K hours on it.

Build a mdf box to mufful
Sound

No to, your noise questions.

Just make sure the fan doesnt surpass the max cfm rating for the filter. easy mistake to make. also make sure you get the light within a foot of the tops... dont want too much stretching. I have hung fans with bungee in my old sketchy apartment grow and that seemed to work well

thanks for the input guys

5x5x9 = 225cf
225cf needs a MINIMUM of 225cfm in air movement rated fan.....Your will work at 50% and I would NOT go lower!
Same need for a filter = 225 minimum cfm rated filter! Ryan is correct! Do not pass the max cfm limit of the filter with your fan!

Doc

roger that