Need help cooling down 2x2 newbie

Ok I need some suggestions, I have 27,27,63 in spider farm kit came with sf-1000 dimmable, Got a viparspec xs1500 tried putting them together way to hot. Upper 80. Took sf light out now says around 81-83 can’t get under 80. Have 6in in-line duct fan with carbon filter haven’t had to use, can normally keep 1 or 2 vent open on tent and cools down. Temperature outside of tent stays around 75-80 have ac.
I know looks messy but have been moving ththings around for a for days trying to find right combo. Thanks for all tips all are needed

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Where are you exhausting your vent to? Are you pulling air from the bottom and out from the top? Where do you have your temperature sensor located? Should be next to the exhaust to catch you exit/high temperature. Try placing a temperature sensor under your canary close to the air intake.
What are your humidity sensors reading?

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Low 80’s is okay.

Cool air in the bottom of the tent and hot air out the top. Airflow is important too.

It can help quite a bit to locate your LED driver-ballast outside of your tent.


It’s most important you keep the air circulation out/in to replace CO2 and stagnant air inside your tent. Unless you are using a closed system then you’ll need to supplement your air with CO2.

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Try running your inline 24/7 on low, should help pull hot air out from the top, replace with fresh Air from bottom vents.


It may not be much, but move the in-line fan outside of the tent.

Absolutely right. I have plants outdoors in Texas heat. They do just fine.


I would suggest blowing out the filter instead of sucking through it. Duct work is probably all full of holes, common issue with spiderfarmer. It’ll be easier on the fan that way.

What Size Inline Fan do I Need?

There are various sizes of grow spaces, each requiring a different amount of airflow to ventilate them. Exchanging stale air inside with fresh air from the outside of your grow space is vital for optimal plant growth. This figure is measured in CFM or cubic feet per minute.

To find the amount of airflow needed for your grow space, first find its volume in cubic feet. Most grow tents’ measurements are given to you in inches, so convert your space’s dimensions from inches to feet. Then multiply its length by its width and height. This will equal your grow space’s volume, with the required airflow equal to this figure in cubic feet per minute, or CFM. Here is what the formula looks like:

For example, a 48”x36”x72” grow tent converted to feet would be a 4’x3’x6’ grow tent. Multiplying the dimensions together would equal 72 ft3. Since a grow space’s volume is also the required CFM to ventilate it every minute, this grow tent’s base CFM is 72. Hold on to this number, as you will have to account for the ducting, carbon filter, and other accessories you might add.


The next step is to increase your base CFM by your accessories’ efficiency percentages. Adding components like ducting and carbon filters will reduce fan performance in your grow space which affects the fan size you need.

When it comes to ducting, the number and sharpness of its [bends]( factor into the airflow resistance. This is because airflow reduces the further it must travel so the straighter the ducting route the better. The sharper the bend, the harsher the efficiency reduction; a 30° bend cuts the amount of airflow by 20% while a 90° bend diminishes airflow by 60%! Smoothing out any wrinkles can also improve fan performance and airflow.

If you are using LED grow lights, you must also account for its heat output which further increases your required CFM by up to 50%.

These factors add to your required CFM, which calls for a high performing fan in order to move the calculated airflow. Because accessories on the market can greatly vary, you can use estimated efficiency percentages depending on the type of component.

(Base CFM x Component factors) x (Grow light heat) = Required CFM

For example, our 4’x3’x6’ grow tent has a baseline CFM of 72 . We multiply this figure by the efficiency percentage of each component. If we add a carbon filter ( 60% ), ducting ( ~20% ), and a silencer ( 20% ) to our ventilation system, we get 166 CFM. From here, factoring in your grow light’s heat output ( ≤50% ) will give us a required CFM of 249 . Keep in mind that these percentages are not fixed and may vary. Here is the breakdown of this calculation:

Multiplying your base CFM (72) by the ducting (20%), carbon filter (60%), silencer (20%), and grow light heat (50%) of your choice will yield about a required 249 CFM.

When shopping for a fan system, we recommend one with fan speed controls and a 25% or greater CFM rating than your minimum requirement, especially if using a filter. This will allow the fan to run quieter at lower speeds and give you room for future grow space system expansion. Look for inline duct fans that use DC fan motors that operate the quietest compared to AC fan motors. PWM-controlled EC motors are acoustically acceptable as well.


Thank y’all so much that’s why this forum is awesome. My my bad specs on fan
【POWERFUL VENTILATION SYSTEM】Quiet and powerful 4” Inline fan and RC412 Australian charcoal carbon filter and flex aluminum ducting combo; very easy to install and use; gives strong air flow and proper air circulation, purify unwanted odors; you won’t smell anything but fresh air. Great for humidity control as well
4 inch not 6 but will trying running it to see what happens, also upgrading tent size soon so now I know will need to upgrade fan as well, thanks again


@LateNightGardner @oldmarine @Dave101 @Budz @MidwestGuy thanks any and tips welcome like said first time, learning curve


I saw a comment on CO2. Adequate airflow, given ambient CO2, is perfectly fine for the vast majority of hobby growers. Supplemental CO2 requires pairing with very high lighting levels, high nutrient levels (without burning the plant,) and a closed environment. CO2 is best used in a hydro environment where high nute levels can be pushed. If you don’t have those in place, then CO2 is a waste of effort and money.


I’d say your best bet for lowering the temp in that space is lowering the outside room temp. You are going to be jumping through hoops otherwise.
Your not going to drop tent temp below the room temp and that light is going to keep it warmer no matter what. Low to mid 80’s is fine.
Also the amount of plants/soil in that space is going to contribute to heat. Can I ask why you went with 3 plants in a space that’s meant for 1, or 2 small, small, autos?


Thank You!

I like your new avatar, @Low. Nicely done.

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So I have no ideal what I’m doing, honestly I thought try 3 hopefully 2 make it. Those 3 are 18 days old from sprout. Just got another light this week, next week upgrading to a 4x2x6 and im hoping with more space will not be as hot as well . Also will me relocating tent to basement/cellar stay around 70 thanks again for all tips please keep them coming


Sounds like a good plan @Kingkupa the basement temps will help big time. Beware of humidity. There’s pros and cons to every environment!

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Not sure if mentioned. Disconnect filter for now til flower when the smelks come and ull get that much more flow pulling out air for now. Id do everything i could to keep both lights in the tent. As being small plants now they dont need a ton of light keep them dialed down low and just watch the stretch. During lights on keep the tent open and that should help alot. If u have any way to exhaust the old air out of the lung room id suggest doing that as u might be adding a small amount of heat into the room that the tent breathes from. If ur close to a window get a window setup for a portable ac unit and vent the exhaust going outside and fresh air from in the room tent is in. Also u might think about if u run central air in the house get a dmall 3 or 4 inch flex tube connected to a lower cinch port and set one end of the tube connected to the conch and the other lay over a vent to take some of the cold ac air and put it directly in the tent to cool it down

@Mark0427 thanks for the tips have a set up now but will hopefully being relocating and upgrading soon for now this is what I have going on, couldn’t get a good pic to much stuff in way so it goes like
13 in metal fan sets over an ac vent have covered up with insulation board, had left over from last winter made a tunnel, runs right in back of ten when ac on can feel the cold air coming in. Didn’t think about taking filter off thank u for that my guys 3 weeks old, so no smell yet . And my exhaust goes out into a different room. Have 2 light sf-1000 running at 100% and viparspec xs 1500 80% hanging at 20 inches. Max temp last few days was 85 but it’s been super hot, normally hangs around 77-80 with 60 humidity but thanks for all tips

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My room hangs aboit 83 to 85 on occasion with my lights cranked. With all the loghts i have about 990 true watts in a 4x7x8 thats including 3 uva bars

Wow that’s a step up, was trying to stay around 80 but it’s good to hear not getting to hot. I’m new and just trying not to mess up to bad, like said before thanks a lot all tips and pointers @Mark0427

Have to watch heat vs rh. U wanna avoid getting white powder milder. Too warm and too much humidity and bam u get wpm. Ill find a vpd chart and u can go off one of them. Summer sux growing for me as i run portable and window ac units so my humidity is always up higher even running dehumidifier all day everyday lol. I hear up to 85 max basically is about the limit i used to freak when id hit 80 now 8e 84 dont bug too much it hits 85 and look out im getting the dry ice ac units and all lol. No not that serious but i freak a bit more as heat causes issues. If u can keep the heat down itll b better. More heat more water so watch that also. If not in flower they dont need alot of light now anyways as long as the stretch is under control and u can keep low watts and lower the light til it seem insufficient light then turn up power a bit and raise if need be depending on height. Its super fun growing. If u enjoy smoking ull love growing after the first run or 2 when all taste so good compared to what u buy else where. Ull b like hells to the yeah

@Mark0427 Yeah I can’t wait until I see a flower, I’ll probably flip out when buds start to appear. Moving my full step to basement / cellar soon already have bigger then needed for my house de-humidifier and air purifier down so stay around 70 all time and I can control humidity. Thanks again