Air circulation/inline fan question...PLEASE HELP

So I have a 4x4 grow tent with two 600watt LED lights...my tent is in a shed on my property..my question is..would I need to get inline fans or could I manage with booster fans? Also, what size would be best...4in or 6in....I'd rather not pay the 69 x 2 if I can do the same with a few $21 booster fans...lol... Thanks in advance for any and all comments and plea see each bare with my newbie questions...haha

Buy a good 5" or 6" inline fan. You probably wont need 2 fans, just extract with a 6" and have a passive intake.
If your planning on using a carbon filter then a booster fan wont do much, it wont handle the pressure needed to draw enough air through a filter.
Think of the value of your tent, light and crop and then ask yourself do you want that crop ruined because you skimped on a fan?
Do you want to deal with poor air flow, bud rot, high temps?

I really like the hydrofarm 8 inch booster fans. i reduce them to 6". They last even with a lot of pressure on them. Best 30-40 bucks ever and a small profile for a 8". Give them a look. Only downside to a booster... you can't control the speed on them with standard reostat fan controllers. Just run em full bore.

Dont risk high temps for what over a couple years is pennies... i had one round get too warm at tail end of flower, was a new grow room, i was new, and hadnt designed room well enough for high ambient temps, and we got a heatwave... they finished and looked fine, almost zero aroma, tasted like hay no matter how long i cured it, and the effects where there but only breifly, very short lived.... i had good rounds from my very first to that one, and what a college course that one was for me on temp...

I don't feel our girls are pansies and actually like a warmish high rh enviornment through mid flower, they grow like an sob... but finishing cool n dry really seems key to quality in my experience...

Booster fans are LOUD. I would do x2 inline. I'm a big fan of the HEPA intake which I imagine would be necessary for a shed to keep the bugs and pollen out.

I use x2 4inch inline on my 4x4 tent 400-600watts lighting. if your two 600 led are an actual watts of under 600 i would do 4inch.

Problem too with boosters is being an axial fan they move a shit ton of air for their power draw... but create little pressure... an inline fan or squirell cage style fan may use more juice to move same amount of air but they create more pressure, meaning they can handle pushing air through ducts, filters, etc. Cfm is not only measurement you need.

Huckster79 said:

Problem too with boosters is being an axial fan they move a shit ton of air for their power draw... but create little pressure... an inline fan or squirell cage style fan may use more juice to move same amount of air but they create more pressure, meaning they can handle pushing air through ducts, filters, etc. Cfm is not only measurement you need.

Click to expand...

Yes, this.
CFM in the system is very different than the numbers on the box of the cheap ones. It's about accurate for the good ones, that's why people buy them even though they are way more expensive.
Look for a used one on Craigslist or ebay if the price is holding you back.

That's not to say the cheapo boosters don't have their place. I just don't recommend them if you plan to grow more than one cycle...and even then, it'll be a battle.

Over size the filter if you use one.

Axial fans are great to just move lots of air, just cant meet resistance.

Sorry for the late reply...I ended up buying a 6 inch inline to exhaust my tent and a 6 inch hydrofarm booster for intake....really thinking about switching my intake fan to a 4 inch inline....any info on that would be appreciated.

Any fan on your inlet is total overkill. A 6" 400cfm fan is more than enough for good exchange in a 4x4 with a passive inlet. Also, I'm sure I'll get resistance on this comment, but your fan should be blowing into the light after pulling from the filter. If it pulls, it will pull unfiltered air from miniscule & unnoticed leaks in the light hood, ducting etc and put unfiltered air outside of your tent. If stealth is paramount, I'd suggest switching it around.

HydroRed said:

Any fan on your inlet is total overkill. A 6" 400cfm fan is more than enough for good exchange in a 4x4 with a passive inlet. Also, I'm sure I'll get resistance on this comment, but your fan should be blowing into the light after pulling from the filter. If it pulls, it will pull unfiltered air from miniscule & unnoticed leaks in the light hood, ducting etc and put unfiltered air outside of your tent. If stealth is paramount, I'd suggest switching it around.

Click to expand...

I'm running LED lights

HONEYCOMBHILLZ said:

I'm running LED lights

Click to expand...

Ah, guess I shoulda read more and answered less haha. I still stick to the 400cfm in a 4x4 and a fan on the inlet being overkill. Unless your walls are collapsing from negative pressure, there's really no need for a booster. You can run passively and save $ on electricity costs by not using a fan at all.

that tent looks familiar. can i see some better pictures? sorry, but im a whore for pics. ok, im not a whore for pics, im just a whore.


5X5


intake. has a nice built in screen. if you have an insect problem, use dryer sheets and duct tape. open both sides for a 6" or bigger.


5X5 big ass carbon filter


5X5 6" inline. bought it used from a friend at 25% cost.


2X4 veg tent with the 4" vivosun squirrel cage.


2X4 with a tiny carbon filter. same intake setup as the 5X5

If noise gets ya put that thing bck in its box, cut holes for the ducting and fill the damn thing up w spray foam. Insane sound reduction and no fan does not overheat in least, as its motor is inline with the fan and its that freshly drawn air through the duct that cools the fan. I then wrapped mine in metalic styrofoam and used plenum tape on edges doesnt look shotty....