need help with ventilation

Hey RIU. Trying something new. I've decided to buy a grow tent and now I need help with ventilation. This will be my first time installing an inline fan and carbon filter. But before I go off and buy them, I want to know what will best suit my tent. Im very limited to space so I'll be using a 2.5'x2'x6'. I was thinking of maybe using a 4 in inline duct fan by Active Air or VenTech at about 190cfm. When I told my buddy this he said that's way more than enough and I should just use a inline booster fan. I always thought booster fans were used as a supplement with the duct fans. Please help because I don't want to be spending to much. Also, how often should the fan be running? I would also prefer something quiet

The fan should be on at all times, unless you're getting too cold in the room. A 200-250cfm on a carbon scrubber is good for that size. Get a turbine fan, they are much quieter than a squirrel cage fan. Make sure you dont just nail it down to something solid, mount it soft, or it will be loud. Booster fans are booster fans, they dont have the umph to pull air through the room and filters.

Good news, tents are pretty easy to ventilate. Bad news, if you are using a carbon filter then duct boosters won't be sufficient. I was able to use two duct boosters blowing in each side of the bottom to cool a 2x2 8 tube t5 in a 2x2x5 tent, but even that was stretching it once I had ladies in there. I ended up using a 160 cfm 4in "radon mitigation fan" from Menards ($130) and a Y to blow in the bottom of two tents. The cool air coming in the bottom forced all of the heat out of the top. I had my girls elevated on a grate just higher than the air input. This worked for the t5 veg tent and also a 150w I was running in the other veg tent.

With the carbon filter I'd imagine you'll be mounting it wherever it fits! If you had to get clever for space restrictions then you could build an external filter chamber that houses your fan/filter and draws air out of the tent, filters it, and then expels it to wherever you're venting. Take my advice and don't short yourself on your fan for short term savings. Look for something with a good warranty (all of a sudden I've had my 6" for 5 years and I'm still using it; I'm glad I went with the 10 year warranty. Also, the last thing you'd want after you find out how much you love doing this is to have to purchase another fan when you upgrade to some ventilated hoods and a bigger area,. If you'll be moving to vented hoods then I'd go with a 6", my 6" cools two 600w XXXL just fine, my girls can touch glass if they ever needed to...the 4" is not used any more.

Hang your fan with strong bungee cords and eliminate vibration noises If you always need the air filtered, then run your fan constantly. If you only need to cool/filter when your lights are on, then run a small oscillating fan (probably clip on with your size restrictions....maybe two or three small ones) and not your big fan to save power during your dark cycle. When temps aren't an issue I've heard of people cycling their fans on 30 off 30 to save power, but I like my lights as cool as possible when they are on. Good luck man!

Just remember, fans suck better than they blow.

check out some of the photos i have posted i also use a fan controller on my blower. i have to keep the cabin pressure right or it will either suck in or look like a bouncy house. LOL i also use 2-3 6 " clip fans to keep air moving. and in mine a heater.. any questions i can answer for you i will try and help.. Growing part not so much but for ventilation i can help

I should have mention that I'll be using 2x kessil h350 (LED) for my lighting, so I don't think heat will be an issue. And I'll be using a 4in organic air charcoal filter (resembles a k&n filter) so I don't have a choice for the size of the fan. But you guys answered my question about booster fans-stay away from them if I'm exhausting air. If I was to use a 4" inline duct exhaust fan at 190cfm will that be enough and will it be exhausting too much CO2? Since heat is not an issue, should I be running it 24 hrs? And is it necessary for an intake fan because of the size of the tent? The tent has a window near the bottom to let air in. Thanks for the reply guys.

No problem. There are quite a few folks around here with an eyebrow up about these LED grow lights, I'm sure if you did a good thread, you'd have a following.

I run 24 hours, everything, only moving the flowering plants into a dark area every 12 hours. Doubles the yield.

ETA. I don't know anything about CO2 except that when the fans come on, it sucks the CO2 out, so you have to be able to control the heat with the fans off.

I am setting up a 3 X 3 tent and ordered a 6" Sunleaves Wind Tunnel inline fan… They got god reviews.

I am going to be running it off a Variac switch that will allow me to lower the fan speed. 400 CFM is waaay too much for a 3 X 3 tent, but I am running a carbon filter and may expand my setup one day down the road…in which case, the extra power may be handy to vent a second, vegging tent or something.

I did a lot of reading the last few days and the Variac switch seemed the safest option that won't cause the fan motor to hum and wear out faster. It was about double the price of a regular Speedster.

next set is 5x5 x6 tent 4 plants 400w and only 4"fan both tents work in conjunction with each other saving on money and equipment. they wake up and go to sleep together. I was told one most important thing STOP READING TOO MUCH lol i just sit back and enjoy the growth all they need is light water air and food.. remember its simple not complex. my first grow here and i say its glorious