Some questions about adding an in-line fan.

[BigBlonde]

We're thinking about adding an in-line fan and have some questions.

Would the AC Infinity T4 model be right for our 107 cu ft tent?

Would it be better to buy the model with the temperature and humidity controller?

Do we need a filter? We aren't worried about the aroma from the plants. Is there anything else to consider? The tent is not in an occupied part of our home.

Background: This is our first grow in a tent under lights. We have a 4x4x6.5 tent with two Viaspectra XS2000 LED lights. We are currently using a 200 CFM fan that pushes air into the tent. We currently growing two Black Jack autoflower plants that are beginning the flowering stage. The plants seem healthy in spite of us having made our share of mistakes.

 

[BigCube]

Strictly speaking. You don't need a fan to push air in to your tent, rather a decent fan blowing out of the tent preferably at the top most part of the tent above the lights to exhaust any humidity and heat that builds up. The tent will passively intake air from its vent flaps out of the room it's in.

If for whatever reason you are piping air in via a fan, the exhaust fan MUST be rated the same or higher otherwise you will be pushing more air into the tent than you are exhausting. Causing the excess air to flow out of the tent seams and vent flaps rendering your exhaust fan useless. You dont need a filter on your exhaust if you're not worried about smell.

200cfm is enough for a 4x4. Hope this helps. I can try and clarify any follow up questions you have.

 

[RootsRuler]

Go with the T6. The ratings are at full speed. You don't want your fan running at full speed all the time. The controller 67 will help regulate the temp/humidity in the tent. Carbon filter is only needed to remove odor.

 

[BigBlonde]

Strictly speaking. You don't need a fan to push air in to your tent, rather a decent fan blowing out of the tent preferably at the top most part of the tent above the lights to exhaust any humidity and heat that builds up. The tent will passively intake air from its vent flaps out of the room it's in.

If for whatever reason you are piping air in via a fan, the exhaust fan MUST be rated the same or higher otherwise you will be pushing more air into the tent than you are exhausting. Causing the excess air to flow out of the tent seams and vent flaps rendering your exhaust fan useless. You dont need a filter on your exhaust if you're not worried about smell.

200cfm is enough for a 4x4. Hope this helps. I can try and clarify any follow up questions you have.

Thanks! I have only one tent fan. I've read some different opinions about pushing air in or pulling it out. I chose to push air in from the top to create positive air pressure. There are two vents open on the opposite side of the tent to exhaust the air. The lights can be hot, so I'm adding small fans to the heat sinks. I have one installed so far and it made a big difference. I'm thinking of adding heat sinks to the power supplies.

 

[BigCube]

You can do both. But a couple things make it advantageous to use exhaust.

1. The exhaust moves all the heat out of the tent and even to room if you just pipe it outside. So the room the tent is in doesnt heat up as much.

2. Filtering an active intake (fan forced air) is harder than filtering and passive intake. For the most part, the mesh on the tent flaps is enough filter to keep out bugs, hair and lint/ household dust because there are several vents and they dint have to work very hard to supply air. But if you're forcing air in the tent without a filter youre likely to get bugs hair lint and dust in your tent and on your plant. Filtering the intake of the fan would cost more and also take up more room since the filter you would need would be large to not restrict airflow.

Also I cant claim any science behind this, but I find my grows always run best when I have a little negative pressure in the tent.

Just some food for thought.

 

[BigBlonde]

Go with the T6. The ratings are at full speed. You don't want your fan running at full speed all the time. The controller 67 will help regulate the temp/humidity in the tent. Carbon filter is only needed to remove odor.

Good point about the speed! I also don't like the noise when a fan is running full speed. The fan I'm using now is very loud.

I'm thinking the controller for an additional $30 is the way to go. I would probably regret not getting it. I guess I'm just not sure about how to use it.

I'll probably pass on the filter, for now. It may be more important when the weather is cold and we won't be able to ventilate the room like we do now.

 

[freezeland2]

I run two ac infinity fans on my tent. I have a 6” as exhaust and a 4” for supply. Both running on same 67 controller with minimum speed at 4 and max 10. Works well. Tent is 3x3.

 

[BigBlonde]

You can do both. But a couple things make it advantageous to use exhaust.

1. The exhaust moves all the heat out of the tent and even to room if you just pipe it outside. So the room the tent is in doesnt heat up as much.

2. Filtering an active intake (fan forced air) is harder than filtering and passive intake. For the most part, the mesh on the tent flaps is enough filter to keep out bugs, hair and lint/ household dust because there are several vents and they dint have to work very hard to supply air. But if you're forcing air in the tent without a filter youre likely to get bugs hair lint and dust in your tent and on your plant. Filtering the intake of the fan would cost more and also take up more room since the filter you would need would be large to not restrict airflow.

Also I cant claim any science behind this, but I find my grows always run best when I have a little negative pressure in the tent.

Just some food for thought.

I'm finding that controlling heat and humidity can be quite a challenge. It depends so much on what the weather is doing. We've had a cold spring and summer so far, so I've had to vent the room during the day and heat it during the night. It's starting to get hot here now, though.

I hadn't thought about sucking debris into the tent. The room is not attached to the house and is relatively clean, but I've cleaned enough filters on air purifiers to know how much crud there can be in the air.

We can certainly try negative air pressure when we get the new fan. It would need to be negative for a filter to do its work. We don't need a filter now, but we might during the colder months.

 

[BigBlonde]

I run two ac infinity fans on my tent. I have a 6” as exhaust and a 4” for supply. Both running on same 67 controller with minimum speed at 4 and max 10. Works well. Tent is 3x3.

Two fans can run on the same controller?! That's very useful information. I haven't got myself so deep into this yet to read product documentation. It seems the AC Infinity fans are a popular choice, so I'll probably go with them.

Why are you using two fans? How do you have them configured? Do you intake at the bottom and exhaust out the top?

 

[BigBlonde]

Here's a day in the life of my plants. I think I need to work on the temperature and humidity changes during the lights-off time (11 PM to 5 AM).

 

[freezeland2]

Two fans can run on the same controller?! That's very useful information. I haven't got myself so deep into this yet to read product documentation. It seems the AC Infinity fans are a popular choice, so I'll probably go with them.

Why are you using two fans? How do you have them configured? Do you intake at the bottom and exhaust out the top?

I run both because passive intake wasnt enough alone to keep temps down and rh where I wanted it and tent sides were always really sucked in. I was also just running 4” originally. Bought the 6” and replaced the 4” as exhaust at top of tent. I took that 4”” and put it as a supply at the bottom. Both are plugged into the same 67 controller which is Bluetooth enabled. I’ll be replacing that controller with ac infinity’s 69 controller that is WiFi enabled.

 

[freezeland2]

Here's a day in the life of my plants. I think I need to work on the temperature and humidity changes during the lights-off time (11 PM to 5 AM).

Do you run a dehumidifier during dark cycle and shut the humidifier off if one is running?

 

[Blastfact]

For a 4x4 tent I would do a 8" AC Infinity so I could get my cfm at lower rpms and keep it quiet. I run a 6" units in my 2x4 and 3x3. Always exhaust air from the top of the tent,,,, Heat rises. I use my exhaust fans to control temp and exhaust excessive humidity into the grow room. The central A/C system has enough capacity to extract the humidity from the living space. I use a Inkbird control to control a 1 gal or 1.3 gal humidifier in the tents when I need to get the RH up in the fall and winter months mostly. I have way more total lighting power in my tents than needed by most peoples measure. In the summer months I can turn the dimmers down, keeps the lights close to the plants and still maintain fantastic light coverage and keep the temps down. Come fall and winter I can raise the lights higher, turn the dimmers up and use the extra heat the lights put out to heat the grow space. This does require a tall tent. I also always keep at least 3ea. 6" small circ fans in the tent. 2ea. in the grow space and one above the light. Always keep them on low to gently move the plant tops around and one above the light on low during the summer months to cool the lights and have the warm air ready to be extracted by the exhaust fan. On high during the fall and winter to force warmer air down into the grow space. Good Luck!

 

[RootsRuler]

For a 4x4 tent I would do a 8" AC Infinity so I could get my cfm at lower rpms and keep it quiet. I run a 6" units in my 2x4 and 3x3. Always exhaust air from the top of the tent,,,, Heat rises. I use my exhaust fans to control temp and exhaust excessive humidity into the grow room. The central A/C system has enough capacity to extract the humidity from the living space. I use a Inkbird control to control a 1 gal or 1.3 gal humidifier in the tents when I need to get the RH up in the fall and winter months mostly. I have way more total lighting power in my tents than needed by most peoples measure. In the summer months I can turn the dimmers down, keeps the lights close to the plants and still maintain fantastic light coverage and keep the temps down. Come fall and winter I can raise the lights higher, turn the dimmers up and use the extra heat the lights put out to heat the grow space. This does require a tall tent. I also always keep at least 3ea. 6" small circ fans in the tent. 2ea. in the grow space and one above the light. Always keep them on low to gently move the plant tops around and one above the light on low during the summer months to cool the lights and have the warm air ready to be extracted by the exhaust fan. On high during the fall and winter to force warmer air down into the grow space. Good Luck!

I agree. I have a T6 in a 5 x 5 and so far it's keeping up with two 2000w LED's but I would like a little more headroom and wish I had gone with the 8" fan. I've set the lung room temp to 73* and the tent is running between 76* and 80* with lights on and 73* to 75* at night. RH is averaging out to around 54% but I'm dehumidifying the lung room. VPD has averaged between .84 and 1.37

 

[MacroLogos]

Good point about the speed! I also don't like the noise when a fan is running full speed. The fan I'm using now is very loud.

I'm thinking the controller for an additional $30 is the way to go. I would probably regret not getting it. I guess I'm just not sure about how to use it.

I'll probably pass on the filter, for now. It may be more important when the weather is cold and we won't be able to ventilate the room like we do now.

Those controllers are easy to learn to use and have a bluetooth app. You can just run them in simple on/off mode until you learn how to use the advanced features (you can create scheduling and triggers to change fan speed at different temp/humidity points).

It also provideds a VPD (Vapor Pressure Deficit) monitoring function which is *very* useful, imo.

I remember my first T6... and now I have 3. I ended up adding fans on 2 of the 4x4x7 tent ports (intake & exhaust for heat control), and I setup an additional 2x4x7 sprout/clone/veg tent/rack and it has a fan..

The AC 67 is a good choice... and if you start with 1 fan, you have the option to add another later... say, if you get a bigger hotter light and need to vent more heat or add a filter, etc.. etc..

The 4 port controller can control 4 fans independently BUT it only has 1 temperature sensor, and so advances features can't be setup in multiple tents - just a heads up on that.

 

[BigCube]

Your main issue is going to be the air you intake. I found it's much easier to climate control the room the tent is in rather than the tent itself. Specially since you're exchanging air at the rate of several tents worth per minute.

If you're taking air from the room the tent is in. It is much easier to control the humidity and temperature of that room than it is the tent.

I use 200cfm for a 3x3. I Scrog tight packed buds and never get pests or mould.

 

[PipeCarver]

We're thinking about adding an in-line fan and have some questions.

Would the AC Infinity T4 model be right for our 107 cu ft tent?

Would it be better to buy the model with the temperature and humidity controller?

Do we need a filter? We aren't worried about the aroma from the plants. Is there anything else to consider? The tent is not in an occupied part of our home.

Background: This is our first grow in a tent under lights. We have a 4x4x6.5 tent with two Viaspectra XS2000 LED lights. We are currently using a 200 CFM fan that pushes air into the tent. We currently growing two Black Jack autoflower plants that are beginning the flowering stage. The plants seem healthy in spite of us having made our share of mistakes.

Hey, I've bought cheap 6" inline fans and added BBQ fan controller's with hot glue on the housing to attach. I then 6" to 4" Y for 2 lines as cool input air sucked from a cooler unheated lower basement with fine mesh drawstring bags ( $1 Dollar store ) over both ends...Its not perfect but keeps out bugs and heavy dust.. My tents exhaust is another cheap 6" inline with same controller and filters, no Y added. I'm not worried about the smell, I can adjust the output air to be close to the input. I add input air because I like to add cooler air into the bottom of my tent.

 

[BigBlonde]

I run both because passive intake wasnt enough alone to keep temps down and rh where I wanted it and tent sides were always really sucked in. I was also just running 4” originally. Bought the 6” and replaced the 4” as exhaust at top of tent. I took that 4”” and put it as a supply at the bottom. Both are plugged into the same 67 controller which is Bluetooth enabled. I’ll be replacing that controller with ac infinity’s 69 controller that is WiFi enabled.

I'm glad I asked.

I'm currently running a 120 mm computer fan rated at 200 CFM. I don't have a way to control its speed. The temp & RH is in range while the lights are on, but not when they're off. We're in the dry season now, which means the ambient humidity is in the 60s.

I looked through the Amazon product description and couldn't confirm which controller is sold with the T4. I did see a lot of reviews complaining about getting the controller without Bluetooth. Some suggest buying the base model and the better controller separately. Many reviewers are also complaining about the T4 not moving enough air.

 

[BigBlonde]

Do you run a dehumidifier during dark cycle and shut the humidifier off if one is running?

I don't have a dehumidifier or humidifier. We usually have high humidity here, so a dehumidifier may be what I need. I may need one of those more than I need to upgrade my ventilation.

 

[freezeland2]

I don't have a dehumidifier or humidifier. We usually have high humidity here, so a dehumidifier may be what I need. I may need one of those more than I need to upgrade my ventilation.

Thinking you need both. Dehumidifier and upgraded exhaust and supply. I’m pretty sure all ac infinity cloudline models with temp & rh control come standard now with the newer Bluetooth enabled 67 controllers. Folks that are getting outdated controllers are probably getting old stock from there local grow shop or other online retailer. Order direct from ac infinity and you’ll get current hardware.