Exhaust fan for 2x2x5.5' 135w qb led grow

Hello everyone

I started a thread on my grow here

I have been fine temp and humidity wise so far during veg, 76 day/68 night, w RH 50-65%.

But I just flipped to flower and want to lower both numbers a bit. I have just been using a hurricane 6" clip fan for my exhaust, with passive intake.

I just closed up the flaps, and added some ducting to both the in and out ports, to make sure light isnt creeping in. This is setup in my office/living room area so I want to keep noise minimal.

I was looking into the AC Infinity Cloudline T4, as it seems like it would be plenty for the exhaust. However I am seeing multiple reports of the smart controller not working properly, and reports that it is both silent, and others that its no quiter than other fans half its price.

What other options should I consider? IPower? Vivosun?

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I don’t know about that. Mine is very quiet, way more quiet than any other fan I’ve had.

I’m not sure what the issue may be with smart control, everyone here seems to work fine. In my opinion the DC speed control on the cloudline fans is well worth the cost even without any of the other features. Any of the other fans that have the DC speed control seem to be more money.


Cool thanks @dbrn32 I most likely will get the AC Infinity, I just wanted some solid confirmation that people liked it on here.

Btw, I saw that issue about the Smart settings on a few of the Amazon reviews, as well as this post on ILGM.

@stale @MT3 what do you say as far as the AC Infinity Cloudline? Any issues with the Smart/Auto setting, or complaints about noise?

I cannot get the Smart setting to work for me. How I think it should work is if I set the min to 70 and alarm to 90, I would expect the fan strength to be proportional to that range. So half strength at 80. It doesn’t work that way.
At least I could never get it to, and their support confirmed as much.

I do like the fan overall. I just think a very small coding change to their controller would make it stellar.


Thanks @stale thats what I was reading elsewhere. Do you have a different fan to suggest or are you happy with it overall? I was also considering a similar looking Terrabloom fan, for 1/2 the price. I also think a regular speed controller could probably be hacked to use a raspberry pi sensor to achieve what u were after. Someone on Amazon asked AC infinity about that and they said they didnt recommend using any controller except theirs.


That is not my understanding of how it was intended to work though correct? I’m assuming support gave you some sort of explanation.

Based on my interpretation of manual, the alarm temp is separate feature. It just notifies you of when that temperature has reached or exceeded whatever the alarm temp set point is.

The way I read smart function was to increase fan speed when temp got over your setting, and then decrease fan speed when temperature got below your setting. My fan does this, so do the other two that I have seen in person. Are you saying that yours doesn’t? Or that it just doesn’t work the way you would like it to?


Nothing mysterious there. The ac infinity fans operate on DC power, most of the inline fans operate on AC power. Thus standard speed controller won’t work.

I think some of the complaints you may have read are a misunderstanding of how the fans work, not that they don’t work. Seems maybe at least in this case.

All good thanks for your explanation @dbrn32. Re-reading the Amazon complaint posts seems like that was the case. I am gonna order it right now, might bug you with questions once it gets here. Ultimately I just need to get my RH to drop, so this will either work or it wont lol.

I do have one more question for you in the meantime. Can I mount this fan outside of my tent?

Since my tent is only 5.5’ tall, if I mount the fan inside the tent, I will be limiting how much I can raise my light. This is my first flower and I am worried I might wind up running out of space. I am using an HLG 135w v2, which doesn’t run very hot at all, so i think i could get it safely like 6 inches from top of tent. I could mount it to a wall or the ceiling even. It would just be pulling the air from the tent a few inches, instead of pushing it from inside the tent out. For now it just dumps into the room. Once I have the a/c on, it will run about 2 feet away to a window to be vented outside.

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You can mount fans outside. You just usually see them inside so they can be suspended from the top. To have the best air movement you just want to minimize the amount of duct used. Some people find a lot less noise when their fans aren’t mounted in a rigid fashion too.

It’s also my understanding that there is now a few different models out there. I’d have to go look close to tell you the differences in features. So just make sure you get what you’re looking for.

Cool thanks again. I will figure it out. Am thinking i might try to put some S hooks into my ceiling, and then i can just do the bungee cord hang method for minimal noise, but still have the fan outside the tent.

Its in my Amazon cart I just need to add a few more items. Should be here Tuesday, will check in later this week :slight_smile:


Sounds good. I hope you like it!

I’ve had 2 in less than a month and still having problems with my cloudline T6. They sent me a whole new replacement. So I changed it all out including all wires and sensor. I’m using it in Auto mode and I’m getting fan failure. No way to disable that alarm. I’m using it for high temp control only, all others OFF, including all temp/humidity alarms.
I think this is happening as the fan is cycling to quick, it doesn’t really ramp up and down to compensate for temp versus how far from set point, what a P.I.D loop would do. I think it’s more of a ON when it gets above setpoint, OFF once its setpoint is reached with no or very little delay. As a programmer, seeing the controller doesn’t have P.I.D., I would have a wider dead band plus 1.5 minus 1.5 from setpoint (setpoint 72 - turn on at 73.5, turn off at 70.5). I think you can get the same results to control the outside environment (if growing in tent) and have a manual speed control fan, my outside room stays about 62, and keep my T6 fan ON 2, since auto doesn’t work to well for me.

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@dbrn32 so with a DC power what needs to be done so it can be used in standard ac outlets.
Note I know enough about electricity to get me in trouble. I also plan on getting the AC Infinity cloudline T6.

Use the power supply that is included with the fan.

Oh ok. Maybe I was overthinking it. Thx

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Hey mate I currently run a cloudline t4 and it is awesome, very quite between speeds 1-6 then 7-10 it gets quite loud but is also moving 200cmh of air so kinda limited to what any company can do with that volume.

I believe with a carbon filter and hiding it in a box to muffle sound would make the noise more managble at higher ranges

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Thanks @NreeG will keep that in mind, I have been fine at the lower speeds so all good. Too much CFM is actually a problem for me anyway, my tent can’t handle it.

This week was one of those rare times when it rained every day. Very rare for LA, but as a result, my humidity (after watering at least) was hitting almost 80% at night with the lights off, and hovering around 70 all day.

I was debating going back and forth about what to do, in terms of buying a humidifier or in room a/c w dehumidifier capabilities. Finally decided on the latter and ordered this > Amazon.com

Rain actually stopped yesterday afternoon, so as of 8am when the lights came on, RH was reading 64%. The unit got here this morning, and I have been running it for an hour, about 2 feet away from my tent. It has filled about an 1/8 of a gallon water jug so far, and the AC probe is currently reading 50% and dropping fast :smile:

Updates and pics after I finish my errands and chores for the day.


Maad that looks like a nice small unit and should be more then capable to handle your grow apace and grow room

If electrical cost are an issue I believe some members of the forum have had varying success with covering top of pot with car windscreen sun reflectors(dunno thier actual technical name…lol), I assume it kinda traps the moisture and prevents evap to a point.
I have also had a small amount of success with a store brought moisture catcher/dehumidifier the crystal/gel kind in plastic tubs but only 65 down to 52 and in very small cabinet

@SoLo304 sorry to hear of your issues with this fan. I have the same fan, and I haven’t had the issues you’ve described. You can set it to have a minimum speed, in just the ON mode. It will follow that minimum speed in AUTO MODE. Just keep that in mind.
If you have more questions, I can at least tell you what my fan is doing.


Yeah, mine in auto will only go as high as it’s set in the ON mode. And it doesn’t gradually ramp up and down. Once it cycles on in auto mode, it goes to where the speed setting is in the ON mode. It goes from 0 to 2 or 3 (depending where I left it in ON mode). I’m used to better temp control. In fairness it does do what its suppose to, automatically turn on and off when needed. I wouldn’t call it SMART mode like described. But my fan failure issue still happening, not in ON mode…yet.