Please help me cool my 22"x36"x63" Agromax tent

PCSPAZ

PCSPAZ

Active Member
I thought I did my math and all this should of not been a problem but I can not get this tent cool.
It would be nice if someone with experience over book smarts could lend some affordable and doable advice.

Below is a run down of equipment, arrangement and temp reading

Hardware
22x36x63 Agromax tent
Lumatek 600w Digital HPS Grow Light
Easy cool 6 hood
Digital 600w HPS Lamp
4" Inline Fan
6" Inline Duct Fan
4" Can Carbon Filter
4" duct solid pipe
6" duct flex pipe
2 6" oscillating fan

Here is how it is hooked up.
passive intake -> ducting -> hood -> ducting - 6" duct fan -> out
There are 2 bends on each side of the hood
Carbon filter -> 4" inline fan -> ducting -> out
There are 3 bends after the 4" inline fan
Main flap at bottom wide open for passive intake (about 5"x24")
2 6 inch oscillating fans blowing from opposite corners
All duct work is sealed with Silver FlexFix HVAC tape

I first took a temp reading at 400 Watt setting but I did not write down temps for the top of tent or bottom of tent
I do remember the Radiant Heat was 110F 12 inches under the light, about middle of tent
This is what started all the testing
Due to the fact there is a huge difference between Radiant and Ambient temperature I got crafty to find what the plant would feel through convection.
(I think I have my understanding of heat transfer right, correct me if I am wrong)
I made some 4"x4"x4" cubes out of radiant barrier and suspended thermometer probes with rubber bands in their center.
I then waited 1 hour with light on before taking readings.
Temp readings are as follows with ambient air outside of tent near base steady at 70F

Top is 1" from tent ceiling, Middle is 12" below glass and bottom is resting on the floor

@ 600 Watts
Top 89F
Middle 99F
Bottom 85F

@ 360 Watts
Top 84F
Middle 86F
Bottom 81F

Everything I have read, I should be able to keep this cool at 400 Watts no probs
As it seems, even 360 is to warm. I figured this 4" inline fan would be enough at 170 CFM and I could run it at 50% power.
Sure enough, I played with the settings and around 50% is where you can watch temp change (goes up a couple degrees)
I also set another 6 inch duct fan at intake forcing air through hood along with the one sucking the air out.
No difference.

My good news on the project is custom Veg/mother box with T5-pll's is dialed in perfect at 78 from top to bottom
Bad news, 2 plants are out growing their home and about to be homeless this winter.

Anyone care to share some knowledge through experience with similar arrangements
TIA
 
What kind of fan? In other words how much did you spend on your 6" fan? If it's not a vortex fan then that's your problem. When I was running hoods I used a 750 cfm 8" vortex fan like this -> http://www.amazon.com/Hydroponics-V...381065295&sr=8-50&keywords=8"+centrifugal+fan the more CFM the better but make sure that the noise isn't too bad from the fan at high speeds. Also is the 6" tube exiting the hood insulated? Where is the AC in your setup?
 
computergroove said:
What kind of fan? In other words how much did you spend on your 6" fan? If it's not a vortex fan then that's your problem. When I was running hoods I used a 750 cfm 8" vortex fan like this -> http://www.amazon.com/Hydroponics-V...381065295&sr=8-50&keywords=8"+centrifugal+fan the more CFM the better but make sure that the noise isn't too bad from the fan at high speeds. Also is the 6" tube exiting the hood insulated? Where is the AC in your setup?
Click to expand...

Complete bullshit there are plenty of fans that put out as much as a vortex and some a lot more.
But what hind of fan is it how many watts? or is it a pos duct booster
what is intake air temp approximately?
 
Does your ducting from the light dump the hot air into the same room as your tent? If so, plumb it out of the room. That will help drop your ambient temps so your not sucking all the hot air right back into your tent.

If there's a hole on the top of your tent, set your 4" fan on the top outside your tent. Then hang your carbon filter as high as you can get it and plumb it to the 4".

What are the fans rated at? If they're inline FANS they should be fine. If they are BOOSTERS, might be a different story...
 
Inline 6" is 160CFM. Its is rated at 42 watts
Its one of those silver duct fans. Connected inside hood at duct port at top of tent
Adding another one for intake just for testing did not change a thing.


Inline 4" is 170 CFM. Rated 80 watts.
This is not a booster fan. It is also mounted at the top in the tent above the hood.
The ducting is not insulated however, it does not feel that warm to the touch, only the hood and glass are warm to the touch.

There is no AC in the mix, I figured with the amount of air exchange @ 70 degrees with passive intake would be enough. No?
If I were to add a room AC and if my math is right I would have to lower the room to 55-60 degrees. Burr.


I am not certain mounting the fans and scrubber outside would lower it much as I was able to find that the 4" fan can be reduced to almost 50% power before I see a change is temp inside the tent.

Could this be a Radiant and Convection prob? How would one adjust that?
Anyone have similar size tent? How do you keep the temps in check?
 
Get a better 6" fan. Not a booster. I think all three of mine are rated around 400 cfm. And you never answered where the hot air from your light goes.
 
Just thinking outside the box as all the answers here are focused around additional cooling, the source of your problem. If you're going to spend any more money on fans/air cooling devices, stop. Buy a 300-400W LED 7/9 band light on e-bay for $200-$250, problem solved... just a thought...
 
The Led light is out of the question. plus I really wanna do HPS for flowering.

Grabbed a small CC with a $1000 limit just for this project and the boss, well she wont let me spend any more.
This tent setup and and the Veg/mother setup almost hit 900 (about what I expected), I am down to a hair over 100 left so trial and error on ideas are limited.
I really thought i did my homework and planned all this out. It really looked good on paper.
The 4" inline high velocity fan sucking the tent air through the carbon scrubber should be exchanging more then enough air per minute. I thought I overkilled what is really required.
I realize I probably never would of been able to run the light at 600W (would be awesome if I could) in this tent, 400W was the target. I would be upset but it is doable if I need to run it at 360. I selected the 600 W adjustable ballast/lamp just cause everything I read, its seems a labor of love. and I will out grow this tent by this time next year. That and warranty will cover both ballast and bulbs even if I run at a lower setting.

From everything I have read, the 6" booster fan should be cooling the hood just fine if used only for the hood and it uses separate intake. ( also 70 degree )
The air that is exhausting out of both tent ports only changes the ambient room temperature by a degree or two. A small fan oscillating near the main door resolved that.
The air temperature at the passive intake just outside of the tent through out the day/night ranges from 69-71. maybe a little cooler over night, but I am sleeping so not checking. The air exhausting out of the tent is not coming in direct contact with intake, I do have a air barrier separating them.

In testing, I placed a probe in the center of a 3 gallon pot of moist soil, placed some white reflective material facing up on top of the pot.
I put this pot directly in front of the intake (70 deg temp on the other side of the tent screen)
Went to bed with light set to 360W. Woke up, the probe reads 80. way to hot for a root zone.

I am really confused. My math says I should not be having these problems.
I am starting to think this is a radiant heat issue, and if I am not mistaken, radiant heat is not cooled by moving air.
I have no idea how to cool radiant heat.

@mightyBUMone,
What size area and what wattage light are you working with on that 400CFM?
 
thecoolman said:
Complete bullshit there are plenty of fans that put out as much as a vortex and some a lot more.
But what hind of fan is it how many watts? or is it a pos duct booster
what is intake air temp approximately?
Click to expand...

I am not talking about the brand Vortex, if there is such a thing, but the technology behind it. When I originally started growing I went to Menards and got a "850 CFM" Attic 8" inline fan that might have been pushing 75 CFM. I got a 750 cfm Vortex/Tornado/whirlwind rated at whatever you want to call it and the difference was night and day and the thing was quiet.
 
PCSPAZ said:
The Led light is out of the question. plus I really wanna do HPS for flowering.

Grabbed a small CC with a $1000 limit just for this project and the boss, well she wont let me spend any more.
This tent setup and and the Veg/mother setup almost hit 900 (about what I expected), I am down to a hair over 100 left so trial and error on ideas are limited.
I really thought i did my homework and planned all this out. It really looked good on paper.
The 4" inline high velocity fan sucking the tent air through the carbon scrubber should be exchanging more then enough air per minute. I thought I overkilled what is really required.
I realize I probably never would of been able to run the light at 600W (would be awesome if I could) in this tent, 400W was the target. I would be upset but it is doable if I need to run it at 360. I selected the 600 W adjustable ballast/lamp just cause everything I read, its seems a labor of love. and I will out grow this tent by this time next year. That and warranty will cover both ballast and bulbs even if I run at a lower setting.

From everything I have read, the 6" booster fan should be cooling the hood just fine if used only for the hood and it uses separate intake. ( also 70 degree )
The air that is exhausting out of both tent ports only changes the ambient room temperature by a degree or two. A small fan oscillating near the main door resolved that.
The air temperature at the passive intake just outside of the tent through out the day/night ranges from 69-71. maybe a little cooler over night, but I am sleeping so not checking. The air exhausting out of the tent is not coming in direct contact with intake, I do have a air barrier separating them.

In testing, I placed a probe in the center of a 3 gallon pot of moist soil, placed some white reflective material facing up on top of the pot.
I put this pot directly in front of the intake (70 deg temp on the other side of the tent screen)
Went to bed with light set to 360W. Woke up, the probe reads 80. way to hot for a root zone.

I am really confused. My math says I should not be having these problems.
I am starting to think this is a radiant heat issue, and if I am not mistaken, radiant heat is not cooled by moving air.
I have no idea how to cool radiant heat.

@mightyBUMone,
What size area and what wattage light are you working with on that 400CFM?
Click to expand...

You can remove most of the heat from a hood with enough airflow - I believe even radiant heat. A fain inside the tent blowing over the top will assist with this too if there is a place for the heat to go. I have heard, not done, that you can bring air from outside (like in a basement or a crawl space) and push it through your room (to outside) to cool it down sufficiently enough to keep a grow going but I believe you need an incredibly powerful fan. I use AC because I get results now. You are using 400 watts? I am having kind of a hard time understanding the setup. Can you open the tent and take a few good pics of the "bends" in the light?
 
I run a 5x5 Growlab with a 1000watt raptor hood. I'll break my set up down for you. Might not work for you, but it keeps me dialed (except for summer, which is why I take a break).

I have a board board over my window with 2 6" holes cut out. On the outside I cracked the window and taped a 3M furnace filter over the 6" holes. On the inside I have ducting connected. The first runs towards my light. Second just goes to the floor near my tents intake.

Run 1 = the first duct comes through the plywood and turns towards my tent. I currently have a 6" booster fan (170 cfm) right before the tent. I was late to flower before summer and without ac shit gets hot. Anyways, I'm about to take it out because it's not needed now and essentially restricting flow. So the ducting goes into my tent through my hood and into a y connection. You can't see it in the pics, but I have a 6" inline fan (440? Cfm) sitting on top of my tent. The y connection is hooked to it so it pulls air through my hood and also pulls air out of my tent. The fan is hooked to a day/night temp controller so when it needs to, it speeds up. This just dumps into my room.

Run 2 = the ducting just runs towards the floor next to my tents intake. I used to run passive intake, but I don't like the sides of the tent sucking in. So I bought another 6" (440? Cfm) fan and attached it to a speed controller to give my tent positive pressure.

I have a third fan (440? Cfm) hooked up to a carbon filter pulling everything out of the room and into the attic (handy cause the attic access was already in the rooms closet). This gives my entire room negative pressure in relation to the rest of my house so no smell exits the room.

I also have a 16" oscillating fan and a 6" under canopy fan inside my tent. I move air. Without ac you kind of have to.


This may not work for you. I use the heat from my 1000w to supplement my 2 veg areas outside the tent and vice versa. But if heat was an issue for me (this is what I should have done myself this June) I would cut a new hole next to my carbon filter in the attic. Then seal all my ducting from the light and straight out of the room.

For some reason it won't load the pictures in order and I can't drag them on my iPad. But you should get the gist of it.

If all else fails, move more air.
 

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