Reddit mentions of VenTech DF4 4" Duct Fan 65 CFM

Sure:

• 4 Buckets from Lowe's
  
• Morsen 216W (55W) Grow light
  
• LED 5050 Strip w/ Power Supply
  
• Timer
  
• Carbon air filter
  
• 4" Inline Fan
  
  
• 4" Ducting
  
• Mylar blankets
  
• A roll of foil tape, roll of black duct tape, and a small bottle of tacky glue from Lowe's
  
• 1 1/4" wood screws from Lowe's
  
• An 80mm PC fan I had from before
  

I have the same size tent and 2 similar galaxyhydros so I will say we have a similar setup. I started with a simple exhaust fan and I will vouch for the fans that are actually made for filters. Simply the massive amount of heat it sucks out is well worth the extra money in itself, plus you will go to almost no smell with a proper fan. I started with this and now I have this and I feel it was well worth the extra money. With the first fan I was consistently over 80-85 degrees but with the second fan I never went over 77. No smell outside the tent

Fan: http://www.amazon.com/gp/aw/d/B00F6BL11U/ref=aw_wl_ov_dp_1_11?colid=2XHLEJUA6N9AQ&coliid=INJZA8XHNGF94
Filter: http://www.amazon.com/gp/aw/d/B005HT0GZ8/ref=aw_wl_ov_dp_1_12?colid=2XHLEJUA6N9AQ&coliid=I4RUWHOCF7T3S

I've used 4 inch duct inline booster fans like this.

Thought I'd chime in. I just got my airbrush compressor and airbrush last Friday. But I'd done a bit of research and had a plan.

I built this out of parts from Amazon totaling $50 and a cardboard box.

The main components are:
An air filter. Try and get something that filters more particulates. Like smoke, mold and pollen, but a nice one if you aren't blowing the stuff outside.

A cheap 4in hose like you'd have behind your dryer.

This thing. Dust Hood for 4-Inch Hose

And the Air Motivator

Though I'd recommend getting a different vent booster, as this one is a bit weak. But it does work. The great thing about a vent booster is 2 fold. It's already 4 inches wide so it fits right on the 4 in hose. And it's at the other end of the hose. So the noise is very muted. Though this fan is pretty quite. I'd say it's more quite than a tiny desk fan.

Oh. And we can't forget. About a kilometer of Duck Tape.

Thanks! I used this fan with this speed controller, but i found the speed controller only worked over a very small range on the dial. I will likely replace the fan when I automate it with a Rapsberry Pi controller.

100 CFM https://www.amazon.com/gp/product/B00F6BL11U/ref=oh_aui_detailpage_o07_s00?ie=UTF8&psc=1

This is my tent https://www.amazon.com/gp/product/B00PXK7IMA/ref=oh_aui_detailpage_o08_s00?ie=UTF8&psc=1

You could get this https://www.amazon.com/gp/aw/d/B00F6BL11U/ref=mp_s_a_1_4?ie=UTF8&qid=1484578858&sr=8-4&pi=AC_SX236_SY340_QL65&keywords=inline+duct+fan&dpPl=1&dpID=41FrUZOvkKL&ref=plSrch and this https://www.amazon.com/gp/aw/d/B00EPE3XHY/ref=mp_s_a_1_1?ie=UTF8&qid=1484578916&sr=8-1&pi=AC_SX236_SY340_QL65&keywords=4+inch+duct&dpPl=1&dpID=5139MLHSyHL&ref=plSrch and use your imagination

I haven't heard of any making them louder than full, but most don't really make it much quieter than full. This could be something to do with the type of fan used or the controllers.

Here is an example of a way to make a carbon filter. This one is meant to be connected to an inline duct fan, which is probably the type I would recommend for your sized space.

http://www.homedepot.com/p/Suncourt-Inductor-6-in-In-Line-Duct-Fan-DB206/100067594

http://www.amazon.com/VenTech-DF4-Duct-Fan-100/dp/B00F6BL11U/ref=lp_13399911_1_1?s=hi&ie=UTF8&qid=1412050146&sr=1-1

You can find them at any big hardware store to check it out in person before buying too if you don't want to order online

Okay I just looked up the fan you were talking about in your original post and if this is the one, then how were you planning on attaching a carbon filter to it? It looks really flat like a jumbo computer fan and doesn't seem like it would be easy to both mount to your box and attach a filter to. Also, that type of fan generally doesn't have very good suction/air pressure. They can have a decent CFM rating and are useful for circulating air within the box or as exhaust fans without a filter, but once you introduce something that impedes the flow, they don't have enough force to push air through well. I originally thought you were talking about this type of fan

Either way, if you do end up getting a speed controller on any kind of fan, it is important when using it to start the fan up at 100% speed, then lower the speed down to your desired setting, not start it at 0 and turn it up or start it at the final speed.