I have a 2x4 Spiderfarmer tent, 2024 version with filter & normal fan attached to the side of the tent and an extra AC Infinity fan on the other side of the tent. So Is an Inline fan different? Does it make a difference in growth? Thank you for all your help in advance x
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the typical difference is air flow volumeâŚthe inline fans are usually less than the exhaust fans and donât have any speed controlsâŚ
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Thank you for your reply. Do I need this, do you think, in a 2x4 tent with two normal fans already?
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So long as you have a way to push air into the bottom of the tent and to extract warm air from the top of the tent.
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The extraction of warm air from the top is fine - the tent kit came with a filter/extractor. That bit is just fine. But how do I âpushâ air into the tent? I already have two fans to circulate air around. How do you push air into the tent?
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Pull open the vents at bottom of the tent a lil bit, it will pull air into tent.
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The exhaust fan can serve the purpose of Pulling fresh air in from the bottom of the tent And exhaust hot Stale air out the top. You donât need an online fan With a small space. As @Bentstick mentioned open a hole at the bottom.
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Thanks, the flaps are always fully open. I just need more air in. I have put in co2 bag and bottle in there as well. Iâve put a small 6" fan at one side of the tent, at the open vent (thatâs very close to the garage door, which I leave open a little). Iâve positioned it right up the tent vent so itâs pumping lots of air in. The extractor is at level 3.
I just a good grow!
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If done right, consider air quality and freshnessâŚwith room fans its moving air around, and they are needed for this, but an inline duct system can draw fresh air from a better source ( outdoors ) and nring thr best aspect of the grest outdoors to your ladies. Its a must. I think the quality of water and air is what makes the end result stronger than the nutes, imo. ( remember you are gonna pull out air too, with a grow tent so thats another fan like the duct down low to keeo it smooth flowing.
#fanspeedistheway
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Thank you, thatâs very informative. Hereâs hoping for bigger plants!
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Yep just tune the intake area to allow for near max flow at 100% power. Running fans in series is inefficient, & an exhaust fan will pull in just as much through a passive intake area as it is able to expel through its exhaust port, so thereâs no need to try & âpushâ air into the growspace. You just have to give the exhaust fan enough intake area, & provided everything else is set up efficiently, the intake area should be much more than the size of the fan port. This is one reason as to why running them in series ends up being inefficient. If you set them both up in parallel (side by side) as exhaust fans & gave them both enough intake area for both of them to hit max flow, that a) is possible to do - unlike when running them in series, & b) would outflow running them in series by a lot, for the same amount of power.
If you add enough intake area to hit the âsweet spotâ with the fan running at 100% power & you still need more airflow through the tent, then youâll want to replace the exhaust fan with a more powerful fan, & then add more intake area to support its flow & get you back into the âsweet spotâ.
âSweet spotâ is enough intake area for the fan to reach nearly its max flow at 100% power, which will leave a little negative pressure in the growspace. Too much intake area & you lose the negative pressure, & also the incoming air continues to lose velocity at the tent intakes, for no increase in CFM. Then the air isnât pluming into the tent & is sticking more to the walls as it travels from the intake(s) to the exhaust fan.
Not sure if I would worry about doing the CO2, just worry about the basics for now.
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Thank you PhotoFinisH for your informative replyâŚI did have to read it more than once, Iâm not as cleaver as some in this hobby when it comes to the technical aspects of The Tent 
But I do understand about the âsweet spotâ on in and out air.
Thank you for your time!
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@PhotoFinisH
why is the pictured air flow diagram âInefficientâ?
The goal is fresh air in and used air out.
The referenced diagram shows in & out.
Thanks.
I use oscillating, cooling, exhaust, and sometimes intake fans.
Controlling temp is difficult, moving air, is not.
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The fans need more than their own port size to reach max flow. So if you have the same sized fans or even different sized fans & run them in series/ one intake one exhaust fan, youâll never be able to get both of them to reach their max flow at 100% power. If I remove the intake fan & replace it with enough intake area for the exhaust fan to reach max flow, Iâll probably be around where I was in terms of flow rate running both fans inline, I might even be able to exceed the max flow that I was able to get when running both inline, & for half the power since Iâm running one fan & not two. Also if I donât have to buy a second fan, I donât have to buy a second fan. But what if I did buy a second one, thinking I needed to put it on the intake? If I take the fan that was on the intake & set it up as a second exhaust fan, & also provide enough intake area for both of them to reach max flow, Iâll probably double the max flow rate as compared to running them inline, for the same power.
My fan needed around 5x intake area before it stopped making a vacuum & reached zero static pressure in the cab. 1x intake area & 80% of the fans energy will make pressure & not flow. Increase intake area to 2x, 3x, 4x, 5x the fans port size, & reduce pressure 20% each time, & make more flow each time. Depending on the fan design it might or might not plot linearally at some points along the performance chart, but that doesnât change the fact that 1x intake would still put it way down on the performance chart & itâs going to need more to reach max flow. The only time this might not work out is if the exhaust fan itself already has a lot of restriction on it such as restrictive filters &/or ducting etc. Then thatâs already a different problem in the first place, & youâd want to take care of that to free up as much flow as possible there first, before moving on to tuning the intake area.
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This is absolutely true, and the exhaust fans are symmetrically shaped and built to drag easily ( physics) that âTHIS IS THE WAYâ.
Might i ask, what type of filtration would be correct and feasible to reach the maxed out, or even 100+% to be obtained?
(If this was said already, i apologize for missing it, i got caught up in the idea and numbers and didnt finish reading the entire post ;~)
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Basically you would have to find a certified filter & then match or exceed itâs specs with your fan choice. So you would want to find a fan that can meet or exceed the CFM at the pressure specified in the filter specs. One issue is that most filters & fans arenât certified, so you donât have enough info to really know what youâre getting. But if the filter is certified & says 500 cfm at 1 hg or however they are measuring the pressure or vacuum, then you look for a fan that can do at least 500 cfm with that much or more pressure on the fan. To know that you need a flow map for the fan, & most grow supply companies donât bother, but fan companies usually will.
Personally I started with a fan that was going to be big & powerful enough for my grow space, & then I built my DIY filter to what I thought would be much bigger than I needed to let that fan flow without much restriction, & thatâs been true even after a slight length reduction of my filter. It flows enough that at first it would pull most of the air through the first third of the filters length, so I had to add a two-stage fabric âchokeâ across the outside of the filter to even out the flow across the length of the filter.
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I understand this, thank you, and luckily i am also a lamp worker who loves to âfumeâ which if you do not have the foggiest, its vaporizing gold and silver to set inside (or out) borocilicate work⌠Meaning i have a couple high quality cfm plug and play ( no variable speed tho) fans, and i can spare 1, (8 inch diameter)âŚi hsve the true specs and know its right so i can stsrt off easy testing properly. Again, i needed some words to absorb for this. There is no filtering the fuming cuz it defeats the purpose of getting the poisons as far away as possible as fast as possible, lol!
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Cool, what fans do you have?
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Thank you guys for all your info, this is truly a wonderful site!
I have a SpiderFarmer inline fan, came with the tent kit and two fans in the tent also.
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My bad, been busy with home generator power awaiting solar installation⌠the fans are 10 inch grow1 inline 790 cfm 2500 rpm air pressure (w.g.) 0.125" 60hz 110-120v. Again my apologies for the time delay.
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