Intake Fan help

Chefman86 said:
Really? So 82 to 85 is perfectly fine for veg and flower? If so I'm golden. I just keep hearing from various sources that 82 to 85 is high, and you wanted to be in between like 77 and 79° for optimal temperature
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82-85 is an ideal temperature for LEDs. I am an experienced grower with plants other than cannabis, just getting back into cannabis. I'm not trying to be an authority but I did research this quite well. People are telling you 77 because that is true when using HID lights, that is because when you use HID lights your ambient temperature may be 77 but your canopy temperature will be more like 85. With LED's there is much less heating up of the canopy from IR and light intensity, so your ambient temperature will be very close to your canopy temperature. Believe it or not with HID's when you are running 77 ambient you will end up with close to the same 85 degree canopy temperature as you do when running LED's at 85 ambient.
 
Light the lighter by a porthole just don’t get it too close to the screen on your burn a hole in it like I did also yes there’s been a lot of studies lately now that LEDs are starting to take over the market... There’s something called vapor point deficit that has a direct correlation with leaf temperature relative humidity and ambient air temperature... H ID lights high pressure sodium lights ceramic metal halide lights all produce a lot of infrared heat that’s why they put out so much more heat than LED’s... In order to stay in the VPD butter zone while growing with LEDs you got to maintain ambient temperatures of 81 to 85°F also you have to follow the VPD correlation with that air temperature as far as relative humidity goes like I said I’m going with optic 1 xls and mars hydro ts2000s I don’t see explosive growth unless my humidity is in the mid 60s and my ambient air temp is in the low 80s and that’s in week 5 of 12/12 I’ll attach a vpd chart
 
dbz said:
82-85 is an ideal temperature for LEDs. I am an experienced grower with plants other than cannabis, just getting back into cannabis. I'm not trying to be an authority but I did research this quite well. People are telling you 77 because that is true when using HID lights, that is because when you use HID lights your ambient temperature may be 77 but your canopy temperature will be more like 85. With LED's there is much less heating up of the canopy from IR and light intensity, so your ambient temperature will be very close to your canopy temperature. Believe it or not with HID's when you are running 77 ambient you will end up with close to the same 85 degree canopy temperature as you do when running LED's at 85 ambient.
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So you don't think really anything is wrong with my temperatures or necessarily my air flow.
 
Buddernugs said:
Light the lighter by a porthole just don’t get it too close to the screen on your burn a hole in it like I did also yes there’s been a lot of studies lately now that LEDs are starting to take over the market... There’s something called vapor point deficit that has a direct correlation with leaf temperature relative humidity and ambient air temperature... H ID lights high pressure sodium lights ceramic metal halide lights all produce a lot of infrared heat that’s why they put out so much more heat than LED’s... In order to stay in the VPD butter zone while growing with LEDs you got to maintain ambient temperatures of 81 to 85°F also you have to follow the VPD correlation with that air temperature as far as relative humidity goes like I said I’m going with optic 1 xls and mars hydro ts2000s I don’t see explosive growth unless my humidity is in the mid 60s and my ambient air temp is in the low 80s and that’s in week 5 of 12/12 I’ll attach a vpd chart
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So you think with the numbers that I gave you with regards to relative humidity and temperature that my setup is doing okay?
 
Chefman86 said:
When you say wierd what do you mean? I mean if the fan is running on speed 7 or 8 and I only have (1) porthole on each side of tent open for 6" ducting for passive intake what is going on? Should I send my AC Infinity T6 back for a new one? I don't have any other vents or portholes open....and it isn't collapsing because of negative pressure. there is a good amount of negative pressure but not enough to bend the tent bars or suck itself into collapsing onto itself.
What do you recommend I do to make sure that that T6 isn't defective?
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As long as you have really strong negative pressure, the fan is fine. I can put my T6 on speed 2 and even with a carbon filter and all the duct ports open I have significant negative pressure. It didn't sound like you had as much, but I guess you do.

The best thing is either bring colder fresh air from outside or cool down the room so passive intake helps to cool the tent. I've had my tent up to 85 degrees with the lights on during the summer recently and the plants seem fine, but I also turn the dimmer down when it gets that hot, so it doesn't get any hotter. It might only get that hot at the end of 12 hours (I run 10 pm on to 10 am off to take advantage of colder nighttime air) so the only time it really gets hot is in the morning.

Controlling humidity will become more important as they grow bigger, and they will take exhaust. Your T6 is plenty big enough for your tent, just focus on getting more passive air intake thru ductwork in the port holes.
 
Buddernugs said:
You need to keep your temps in the 81-83f range when running LED’s to accommodate vpd this is now a proven fact your temps are fine just bump humidity up look into vpd charts that should be every growers bible
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Do you have any suggestions on where I could find the information and charts you mentioned above?
 
Chefman86 said:
Yeah I would definitely be interested in some kind of link that could give me more information on those charts. Is that black dog LED charts?
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Just google for VPD, there are a plethora of sources.
Black Dog does recommend that, but the same is true for almost all LED lights. Just google LST LED lights and you should come up with quite a few answers or ambient grow temp LED.
I don't have a place handy specifically to cite, but a lot of growers here that are using LED and much more knowledgeable than me say the same thing.
It's just that growing under HID has been done far longer than LED so your generic info out there will lead you to mid 70 temp recommendations.
 
Chefman86 said:
Would you recommend putting in a small four or six inch active air intake inline fan to help with this problem?
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If the intake fan has much lower cfm than the exhaust is capable of then it actually restricts the intake rather than helps it.

If you increase the exhaust rate so you have even faster airflow it should help reduce temps but if you can change the air in under a minute like your calculations indicate that should be enough I would think.

Other than that I'd say AC was the only other option.

I thought LEDs were supposed to solve this heat problem. ;)

:peace:
 
Chefman86 said:
Really? So 82 to 85 is perfectly fine for veg and flower? If so I'm golden. I just keep hearing from various sources that 82 to 85 is high, and you wanted to be in between like 77 and 79° for optimal temperature
Click to expand...

I aim for 75 unless I'm adding CO2 then I want 85 or more. Right now it's at 77F and 60%rh with a 600W MH going at 100%. I never dim. I have a remote sensor in the grow room and the LCD display right above my monitor so can easily keep track of the temp in there.

:peace:
 
Buddernugs said:
You ever figure it out
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Yes I have found that I do have a little negative pressure but it's not something that I need to buy an intake fan for. I opened up a passive intake ducts down low on both sides of my tent and have a 6-in piece of ducting coming out with a filter and pantyhose attached. I did the pantyhose because they're black and it will reduce light from going in my tent when flower comes. My AC infinity T6 fan seems to be running at 7 or 8 out of 10 speed and keeping my tent around 84 to 85 degrees with 55 to 60% humidity.
I'm thinking things are going to be just fine. I think when my flowering comes in I need to buy a dehumidifier to get that humidity down to say 40 to 45%?
 
No need to drop it that low I don’t know where the whole low rh% during flower came from but it’s not necessary follow that vpd chart religiously and you’ll kill it trust me...your temp is holding at 85f so your rh should be at 60-65%rh when flower hits set up some fans in that area and you won’t have to worry about bud rot
 
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