4x4 tent 600w HPS airflow help

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Xsoldiercloud

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Hey guys I would like some suggestions about properly cooling this 4x4 tent setup with a 600 w hps light here is my current airflow setup that I'm looking to improve:
4x4 tent 600w hps airflow help


4x4 tent 600w hps airflow help 2

4x4 tent 600w hps airflow help 3


I've got a 402 CFM inline fan pushing air from outside of the tent through the lamp however I don't have it venting out. I'm thinking I need to add another HVAC hose to vent the lamp air out of the tent.

As you can see I also have a 402 CFM exhaust fan connected to filter inside to pull air out.

My question is if I vent the air out of the tent does that mean I need to add an additional inline fan to push fresh air in? With this current inneficient setup it got to about 77 degrees at the tent floor with the lamp at full power about 3 feet from the floor. Apparently I should also add a filter to the intake fan to reduce the particles etc that get into the tent?

Another question: would you recommend I connect the intake fan directly to the lamp and instead use the hose to reach out of the tent? Does it matter that I currently have the intake fan outside of the tent with the hose going into the tent and connecting to the light? Thanks in advance guys! I'm trying to get my temps to 73-75 maximum running the light at full power for 8 and 8 cycles
 
Mikedin

Mikedin

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Hey guys I would like some suggestions about properly cooling this 4x4 tent setup with a 600 w hps light here is my current airflow setup that I'm looking to improve:
View attachment 1252312

View attachment 1252313
View attachment 1252314

I've got a 402 CFM inline fan pushing air from outside of the tent through the lamp however I don't have it venting out. I'm thinking I need to add another HVAC hose to vent the lamp air out of the tent.

As you can see I also have a 402 CFM exhaust fan connected to filter inside to pull air out.

My question is if I vent the air out of the tent does that mean I need to add an additional inline fan to push fresh air in? With this current inneficient setup it got to about 77 degrees at the tent floor with the lamp at full power about 3 feet from the floor. Apparently I should also add a filter to the intake fan to reduce the particles etc that get into the tent?

Another question: would you recommend I connect the intake fan directly to the lamp and instead use the hose to reach out of the tent? Does it matter that I currently have the intake fan outside of the tent with the hose going into the tent and connecting to the light? Thanks in advance guys! I'm trying to get my temps to 73-75 maximum running the light at full power for 8 and 8 cycles
Is there a reason you want to stay at 73-75 max? You should be good up to 80-82 and if you’re living somewhere like me with high humidity that hot dry air from the hood would be great right now to drop my RH down? You could pull from the hood through the fan to vent out and just leave a flap or 2 open on the bottom of the tent, best way to test would be trial and error but with HPS I’d imagine pushing through the hood and out of the tent on the other end would lower your temps the most so you don’t dump the heat from the lamp into the tent
 
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Xsoldiercloud

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Is there a reason you want to stay at 73-75 max? You should be good up to 80-82 and if you’re living somewhere like me with high humidity that hot dry air from the hood would be great right now to drop my RH down? You could pull from the hood through the fan to vent out and just leave a flap or 2 open on the bottom of the tent, best way to test would be trial and error but with HPS I’d imagine pushing through the hood and out of the tent on the other end would lower your temps the most so you don’t dump the heat from the lamp into the tent
Hey thanks for the reply. I just read that 78 is pretty much optimal. My test was for about 2 hours. Worried it's going to get hotter than 80 after several hours and stunt growth. Just wondering if I should ultimately be venting that hood air out the tent. Truthfully when I put my hand at the other end of the hood it doesn't feel like hot air coming out. Feel kinda cool.
 
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Xsoldiercloud

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I suppose the other thing is the light would ultimately not be super close to the floor during vegetative growth and flowering so that would probably impact the relative temperature of the tent as well since my exhaust is going up and out. Testing is probably going to be key like you said. I just wanted to know if with these setups it's common to vent that air you push through the light hood out of the tent or not.
 
Mikedin

Mikedin

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I suppose the other thing is the light would ultimately not be super close to the floor during vegetative growth and flowering so that would probably impact the relative temperature of the tent as well since my exhaust is going up and out. Testing is probably going to be key like you said. I just wanted to know if with these setups it's common to vent that air you push through the light hood out of the tent or not.
I use LED but from what I understand yes normally it would be vented through the hood then out of the tent as HPS usually increases temps and the hood venting is meant to push it out, here’s a helpful link for temps /RH /leaf temps during different stages that was given to me

Vpdchart.com

My tent runs up to 82-83f on a regular basis and have seen no slowdown of growth
 
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Xsoldiercloud

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Yeah that's what I was thinking was just wondering what this would do to the clean air in the the tent if I am ultimately going to be venting that air out. The first reply said I could open the bottom flaps to help with ventilation as well. The thing is I have an extra 6" inline fan still boxed up that I was contemplating on adding to the setup. However ideally I would like to return it since it was ordered by mistake.
 
Mikedin

Mikedin

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Yes that drawing is what I mean , even for LED I’m using the 6” vent / carbon filter as my main exhaust, 2 bottom flaps open on the tent, but then I have a 4” hooked up that only kicks on at 30% power if the humidity increases over 60%

Probably doesn’t hurt to have the 2nd fan laying around or just put into use if you already have it

But like the comment above, think about the conditions of your lung room if you are venting back into it, as that air will be pulled back into your tent again, my 6” vents outside, but the 4” vents back to the lung room
 
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Xsoldiercloud

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yeah that's what these 2 openings left & right are for, the top one for the tent air

still, @OP think about your lung-room conditions in terms of high rH
I don't really have a lung room so to speak. It's just my whole basement if you want to consider that the lung room. I just bought a decent dehumidifier for my basement from home Depot coincidentally. RH humidity seemed to be around 55-58% outside of the tent. That should be ok right?
 
Ponky

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If you want the heat gone you can install a insulated exhaust duct hose and run it out of a window. Thats what I do. AC window kits are great for hooking up.
Screenshot 20220610 112205 Amazon Shopping
 
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Xsoldiercloud

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Yes that drawing is what I mean , even for LED I’m using the 6” vent / carbon filter as my main exhaust, 2 bottom flaps open on the tent, but then I have a 4” hooked up that only kicks on at 30% power if the humidity increases over 60%

Probably doesn’t hurt to have the 2nd fan laying around or just put into use if you already have it

But like the comment above, think about the conditions of your lung room if you are venting back into it, as that air will be pulled back into your tent again, my 6” vents outside, but the 4” vents back to the lung room
Nice I'm excited to get going on my very first grow. Did a lot of research on lights and decided to go with the 600w HPS light as I read it produces great growth in a 4x4 setup. I knew cooling was going to require some extra work. I guess on the bright side keeping the tent at a good temperature during the winter is going to be easier haha
 
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Xsoldiercloud

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If you want the heat gone you can install a insulated exhaust duct hose and run it out of a window. Thats what I do. AC window kits are great for hooking up.View attachment 1252483
Hey my old portable AC came with one of those window attachments! Currently my exhaust hose just kinda dangles out of the tent. As I mentioned my lung room is the rest of the basement and it's a pretty large space that stays cool. It's no more than like 70 degrees outside of the tent when I'm up and running. I'll keep this in mind in the event that the space starts to heat up or I can't control the RH with my basement dehumidifier after some further testing.
 
Cashmeh

Cashmeh

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Id move your fan outside the tent and just do what I do. Im running a 1000w hps at that. Super easy to cool like this. Now i have a booster fan also pushing air in. I find blowing the tent up gives you a bit more room on the inside too ;)

Dial in the leaf temps to 77f using your fans not your light. Run your lights on max and your fans on max and you should only be about 2f higher than your outside room temp. Use the it gun and get ur leaf temps up to 76 by slowing down the ehaust fan. Im using an infinity 8 inch which can handle the heat. My last fan had a bearing go out and it fried my plants. This is why i like having a backup fan pushing in.
 
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SmokinJo421

SmokinJo421

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Hey thanks for the reply. I just read that 78 is pretty much optimal. My test was for about 2 hours. Worried it's going to get hotter than 80 after several hours and stunt growth. Just wondering if I should ultimately be venting that hood air out the tent. Truthfully when I put my hand at the other end of the hood it doesn't feel like hot air coming out. Feel kinda cool.
77°f. Is optimal temp for indoor grows.
However temp changes within15-20degrees is not a bad thing.
Next, you DO NOT want to veg under hps!! Your cutting yourself short on bud sites and vigorous bushy growth.
Do you have the ballast for your light in the tent or attached to the tent? Ballasts are way too hot in h.i.d lighting
When it comes to vent fans bigger is better.
You may need push/pull concept from the vent fans. Each motor running in the tent is more heat too
 
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