4x4 tent trouble

Hello everyone,

I setup my new 4x4 grow tent earlier this week and powered it up to dial in my temp before I start my grow. Well turns out originally I was getting temperatures of 85 to 87. I spoke to a local grown shop and he told me it was cause of my in line fan being subpar so I replaced my active air 6 inch with a max fan pro series 6 inch which in turn only helped by 1 to 2 degrees at then most. So I decided maybe I should buy new ducting rather them the crap I had from lowes that was 6 years old but never used. Luckily it lowered my temp I had a steady 77 on top of my hood and 79.1 on the floor 3 hours later the tent climbed over 80 it's currently been on almost 5 hours I got 82.9 on top of hood 84.9 floor.

So here's a break down the room that the tent is in was 65 before the tent came on the setup is

4x4x72 lighthouse hydroponic tent
600w hps
6 inch max fan pro series

Ventilation setup
Carbon filter - (pull) fan (push) - duct - light - exhaust out door (door cracked just enough for vent to go into hall)
Currently the carbon filter is disconnected since it is a 4 inch carbon filter with a 6 to 4 flange I figured at first that may have have been the cause.


So I think I may know what my problem is but would like some insight to see if anyone comes up with something different.

I am thinking I may have to run a active intake instead of the passive vents on the bottom I believe the vents that are open on the tent are reflecting off my white walls and heating up the room the tent is in thus raising my Temps any ideas?
And if this is what I need can I get away with a 4 inch intake and how much come would I need?

Please help thanks in advance!

So I had the same problem in my tent, also 4x4 & a 600w (with side lighting), so pretty much the same setup. You could try an active intake, even better if you have somewhere to pull cold air from, but either way that would probably get your temps where you want them to be once you had it dialed in. Question, do you have a cool tube or air cooled hood? I didn't see that in your explanation. That would help too, and probably be a bit cheaper than buying a fan for active intake or roughly the same price. Either way you have a couple options, active intake being one, buying a cool tube or air cooled hood to move the hot air out of the tent is another, or buying another fan and having one fan dedicated to just scrubbing while the other can cool the light (this would require both a cooled hood and an extra fan so not the most feasible option).

What I did to fix my problem is a I bought a separate 6in inline fan just to push/pull cold/hot air over the light and exhaust it to another room, but I already had a cool tube so the only extra purchase for me was the additional fan. Then I kept my other 6in fan and have it connected to the carbon filter scrubbing the air, and then I just have the vents on the bottom open for passive intake. Idk, works for me maybe it's a little overkill but I feel it gives me excellent control over my environment and temps

Oh my bad lol I forgot to mention yes I have a 6 inch air cooled hood. I don't have any were to pull cold air from was just going to intake from the room the tent is in.

it warmer on the floor than above u light.having hard time grasping that duct bosters cheap,

nsb823 said:

Oh my bad lol I forgot to mention yes I have a 6 inch air cooled hood. I don't have any were to pull cold air from was just going to intake from the room the tent is in.

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Well then I'd definitely go with another inline fan, either a 4in or even better a 6in. That way you can play around with it. You could either try it as an active intake, see how that works for ya, or you can dedicate one fan to blowing cold air over the light then exhausting it and the other fan can be used to scrub the air while keeping the passive intake. It would give you options which is always a plus imo

astronautrob said:

Well then I'd definitely go with another inline fan, either a 4in or even better a 6in. That way you can play around with it. You could either try it as an active intake, see how that works for ya, or you can dedicate one fan to blowing cold air over the light then exhausting it and the other fan can be used to scrub the air while keeping the passive intake. It would give you options which is always a plus imo

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The reason I mentioned a 4 inch fan is the only ducts I have at the bottom are 4 inch not six and I'd assume u want your intake at the lowest point.

thumper60 said:

it warmer on the floor than above u light.having hard time grasping that duct bosters cheap,

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I have a thermometer on top of my hood then I have another on with a probe the probes on the floor and the thermometer is outside the tent and yes there is a 2 degree diff between floor and on top of the hood the floor being the hotter one....

nsb823 said:

The reason I mentioned a 4 inch fan is the only ducts I have at the bottom are 4 inch not six and I'd assume u want your intake at the lowest point.

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Yea if you were going to do an active intake it's usually preferred to have it on the bottom but it's not super crucial. Work with what you have. You could try the 4in though, that would probably work. You could also look in to getting a reducer for the 6in to fit a 4in, I've never done that but I know some who have

You're always going to be somewhere around 5-10 degrees hotter in the tent versus the ambient temperature of the room it's in. What is the room temperature where the tent is located?

Also, don't listen to people at the hydro store, they're salesmen and not growing experts. If a guy told you that your 6" fan was the reason why your temps were high and then sold you another 6" fan (likely with very comparable CFM ratings) then he's taking advantage of you for the sake of making a sale.

lawlrus said:

You're always going to be somewhere around 5-10 degrees hotter in the tent versus the ambient temperature of the room it's in. What is the room temperature where the tent is located?

Also, don't listen to people at the hydro store, they're salesmen and not growing experts. If a guy told you that your 6" fan was the reason why your temps were high and then sold you another 6" fan (likely with very comparable CFM ratings) then he's taking advantage of you for the sake of making a sale.

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the temp of the room the fan is in is between 65-68

astronautrob said:

Yea if you were going to do an active intake it's usually preferred to have it on the bottom but it's not super crucial. Work with what you have. You could try the 4in though, that would probably work. You could also look in to getting a reducer for the 6in to fit a 4in, I've never done that but I know some who have

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I guess I'll get another 6 inch max fan my only issue is noise I gotta figure out how to quiet them a bit more. In gonna try carbon filter -fan -exhaust and a separate intake and exhaust for my a.c light now what's better to cool light fan on intake side or exhaust side

nsb823 said:

I guess I'll get another 6 inch max fan my only issue is noise I gotta figure out how to quiet them a bit more. In gonna try carbon filter -fan -exhaust and a separate intake and exhaust for my a.c light now what's better to cool light fan on intake side or exhaust side

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Yea noise can be a problem. If you have the option to hang the fan from the ceiling or somewhere bungee cords work great for reducing the noise of the fan, that's what I use. To answer your question though, and I hope I understood it correctly, if your exhausting the hot air out of the room I don't think it would matter much if you put the fan cooling the light on the intake or exhaust side. Did I understand your question correctly?

Ya you answered it correctly. I bought another 6 inch max fan yesterday for 200 I'll be hooking it up after work today. I'll keep you posted on verdict

Well I see you already purchased the fan, but if you haven't plugged it in yet I would simply change the placement of your fan. Instead just have the ducting run from your carbon filter, straight into the light/hood, and your fan pulling air directly from the hood. In line fans work much more efficiently when pulling air than pushing. And if you didn't already buy the 6 inch fan, I would say another 4inch fan would do the trick, if placed where your current fan is along with the setup I described.
Ambient temperature is the biggest factor here. You can try to pull air in faster by adding a fan used exclusively for that purpose. But the rate at which your removing heat hasn't increased. It's better to eliminate the issue than to constantly fight it. Make sense. The faster you can pull that air past the light, the cooler the room will be. At the same time you want to make sure your carbon filter is rated to handle the cfm rating, other wise your filter will not be doing its job effectively. Hope that helps.

rickymac21 said:

Well I see you already purchased the fan, but if you haven't plugged it in yet I would simply change the placement of your fan. Instead just have the ducting run from your carbon filter, straight into the light/hood, and your fan pulling air directly from the hood. In line fans work much more efficiently when pulling air than pushing. And if you didn't already buy the 6 inch fan, I would say another 4inch fan would do the trick, if placed where your current fan is along with the setup I described.
Ambient temperature is the biggest factor here. You can try to pull air in faster by adding a fan used exclusively for that purpose. But the rate at which your removing heat hasn't increased. It's better to eliminate the issue than to constantly fight it. Make sense. The faster you can pull that air past the light, the cooler the room will be. At the same time you want to make sure your carbon filter is rated to handle the cfm rating, other wise your filter will not be doing its job effectively. Hope that helps.

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I didn't end up opening the 2nd 6in max fan yet since I was busy yesterday. So my carbon filter is a can lite 4 inch with a 4 to 6 conversion with a 250cfm rating because initially I was going to run my original active air 6 inch at half speed due to noise. Currently I have a 6 inch max fan pro which is a lot quieter but it's rated at 420cfm I have been running it with the carbon filter detached as I am doing a dry run (empty tent) to dial in temps. The reason I had it disconnected was someone said that could be restricting my air flow

rickymac21 said:

Well I see you already purchased the fan, but if you haven't plugged it in yet I would simply change the placement of your fan. Instead just have the ducting run from your carbon filter, straight into the light/hood, and your fan pulling air directly from the hood. In line fans work much more efficiently when pulling air than pushing. And if you didn't already buy the 6 inch fan, I would say another 4inch fan would do the trick, if placed where your current fan is along with the setup I described.
Ambient temperature is the biggest factor here. You can try to pull air in faster by adding a fan used exclusively for that purpose. But the rate at which your removing heat hasn't increased. It's better to eliminate the issue than to constantly fight it. Make sense. The faster you can pull that air past the light, the cooler the room will be. At the same time you want to make sure your carbon filter is rated to handle the cfm rating, other wise your filter will not be doing its job effectively. Hope that helps.

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So I just turned on my tent gonna see how it goes I'll upload a video so u can come how I ran it


Video of setup https://vid.me/isMm

There is no doubt the carbon will restrict the air flow. But its the best way to go in my opinion if your not running a sealed room.

I did watch the video which was aprreciated.. it should work just fine like that but I would recommend mounting that fan directly to the hood. That's how those fans were designed, plus it would essentially be pulling directly from the bulb itself. Now the difference it makes might be minimal, but why not. Lol
As for rhetoric filter you may just have to find out if it will be sufficient. But you might end up needing a larger one to compensate for the can fan. The pros to running the carbon filter with your exhaust are obvious; extra air flow due to negative pressure created within the room, which also lowers temps. The down side is the stinky air is only being filtered one time passing through the system before being exhausted for everyone to smell. That is unless your filter has a large enough surface area to allow the passing air to come in contact with the carbon for a longer period of time. This is why i would recommend a larger filter.
Running a closed loop system would allow for a smaller filter and fan because the air your scrubbing is exiting the room at much slower rate. Thus allowing the air to be 'cleaned' continuously. The downside is less air flow/exchange without the use of high powered intake and exhaust fans ( which defeats the purpose of scrubbing the air ).
Just a few things to keep in mind there.
All in all you seem to be in good shape with temperature control. Smell control you might find yourself wanting a larger filter in the future. Just depends on how stanky those ladies are.

rickymac21 said:

There is no doubt the carbon will restrict the air flow. But its the best way to go in my opinion if your not running a sealed room.

I did watch the video which was aprreciated.. it should work just fine like that but I would recommend mounting that fan directly to the hood. That's how those fans were designed, plus it would essentially be pulling directly from the bulb itself. Now the difference it makes might be minimal, but why not. Lol
As for rhetoric filter you may just have to find out if it will be sufficient. But you might end up needing a larger one to compensate for the can fan. The pros to running the carbon filter with your exhaust are obvious; extra air flow due to negative pressure created within the room, which also lowers temps. The down side is the stinky air is only being filtered one time passing through the system before being exhausted for everyone to smell. That is unless your filter has a large enough surface area to allow the passing air to come in contact with the carbon for a longer period of time. This is why i would recommend a larger filter.
Running a closed loop system would allow for a smaller filter and fan because the air your scrubbing is exiting the room at much slower rate. Thus allowing the air to be 'cleaned' continuously. The downside is less air flow/exchange without the use of high powered intake and exhaust fans ( which defeats the purpose of scrubbing the air ).
Just a few things to keep in mind there.
All in all you seem to be in good shape with temperature control. Smell control you might find yourself wanting a larger filter in the future. Just depends on how stanky those ladies are.

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Thanks for the input I will definately think about a larger carbon in future. So a little update on yesterday it maintained 78.4 to 78.8 for a good 16 hours when I checked 20 hours on it was at 80.8 so I decided to add the second fan in place and turn it back on currently it's a 79.9 thermometer ontop light with the two fans at full blast. Have the probe right above the pots I thru in the start last night and It is 74.6 I will take a video is a little bit.

https://vid.me/KpVT so the temp went over 80 same with top of pots I shut tent down after it got up to 82.9 and opened a window for fresh air and moved pots under a fluro. I'm only gonna run lights for 18/6 last night I had the lights on for a good 20 21 hours before I added 2nd fan so I believe that the room the tents in might have became to warm on top of the fact it was around 1130 noon when the temps reached 82 when normally my tents not gonna be on at this time any ideas

Well you may need to get a portable a/c. With your setup it will definitely lower your temps....