High Humidity when lights turn off?

ZuuTeD614

Well-Known Member
I have a 2'x4'x84" tent I use in my garage. I have 1 4" AC Infinity inline fan pulling fresh air fromy house(temp-70 humidity-45) and 1 AC infinity fan in my tent venting all bad air into my attic and outside. My Temps stay perfect until my lights shut off I have a dehumidifier in the tent set at 40 percent because I'm about to flip lights to 12 12 but hunidity jumps to almost 65 percent. Is tjat because my garage has to much moisture? Should I get a decent dehumidifier in my garage for when my lights shut off? PS I leave both my inlines fans running on a low setting. Intake- 3-4 speed and I keep outtake speed on 1-2 speed settings. If that's helps any?
 

vortexya

Active Member
If you get he 67 controller for the AC Infinity you can way better program the environmental triggers. If you are pulling in air from the lung room (house) at 45% RH and it is hitting 65 % sounds like lack of air flow (out). You should have a negative pressure in the growing space so exhaust should be higher flow than intake. I am guessing the increase in RH is 'cause the drying effect from the heat from the lights is gone in the dark cycle. That controller is fucking magic.
 

ZuuTeD614

Well-Known Member
If you get he 67 controller for the AC Infinity you can way better program the environmental triggers. If you are pulling in air from the lung room (house) at 45% RH and it is hitting 65 % sounds like lack of air flow (out). You should have a negative pressure in the growing space so exhaust should be higher flow than intake. I am guessing the increase in RH is 'cause the drying effect from the heat from the lights is gone in the dark cycle. That controller is fucking magic.
Ok I run my intake higher than my outtake I will fix that, but my lights are 2 -300-60 LED Mars Hydro I can sleep on them. Lol
 

ZuuTeD614

Well-Known Member
If you get he 67 controller for the AC Infinity you can way better program the environmental triggers. If you are pulling in air from the lung room (house) at 45% RH and it is hitting 65 % sounds like lack of air flow (out). You should have a negative pressure in the growing space so exhaust should be higher flow than intake. I am guessing the increase in RH is 'cause the drying effect from the heat from the lights is gone in the dark cycle. That controller is fucking magic.
And with that 67 infinity controller does it hook up intake fan to ine slot and out take to another spot in the remote and I program what I want and the fans work with eachother pretty much?
 

vortexya

Active Member
If the AC infinity fans are compatible, they both go into the respective Molex ports. And yep if you set them up correctly they will work together. Im using a Mars Hydro FC6500 and it has a detachable driver which is a nice idea, if its too cold put the controller in the tent , if its too hot take it outside. The 67 will give you better options but it takes a bit of learning, it is bluetooth and has logging so you can check the grow over time. Here is the manual for the 67. enjoy bro.
 

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ZuuTeD614

Well-Known Member
If the AC infinity fans are compatible, they both go into the respective Molex ports. And yep if you set them up correctly they will work together. Im using a Mars Hydro FC6500 and it has a detachable driver which is a nice idea, if its too cold put the controller in the tent , if its too hot take it outside. The 67 will give you better options but it takes a bit of learning, it is bluetooth and has logging so you can check the grow over time. Here is the manual for the 67. enjoy bro.
Hell yah 50 bucks definitely going to get ahold of that. But you don't think my tent being in the garage doesn't have to do with anything?
 

Star Dog

Well-Known Member
A controller is a very useful tool but it's still going to pull the same air as it is atm it won't change your problem.

What is your light out temps?

At a guess It sounds like the temperature dropping might be creating a rise in rh% so it might be heat related more than moisture, rh is relative humidity, how much humidity for a given temperature, change the temperature and the rh% changes even though its the same amount of moisture.

During the dark period I need 20/21c with the fan running at 10/12% + dehumidifier to maintain around 55%.

40% imo is unnecessarily low I'd wait to later in flower before lowering it to around 45/50%.

50/55% is the lowest I can ever expect and I've not had any rot problems at all with the last 8/10 crops...packed crops I should add.
 

ZuuTeD614

Well-Known Member
My Temps with lights on stay around 78-82 and lights off maybe a 10 to 15 degree lower. So veg and early bud stage 50-55 is fine and then 40-45 late in flower?
 

Star Dog

Well-Known Member
My Temps with lights on stay around 78-82 and lights off maybe a 10 to 15 degree lower. So veg and early bud stage 50-55 is fine and then 40-45 late in flower?
Yes early bud 50/55% is absolutely fine.
It's your temperature dropping that's causing the rh to rise, if you add heat and some constant or interval ventilation you'll sort that rh% out.
 

ZuuTeD614

Well-Known Member
Yes early bud 50/55% is absolutely fine.
It's your temperature dropping that's causing the rh to rise, if you add heat and some constant or interval ventilation you'll sort that rh% out.
So maybe before my lights shut off maybe turn my intake fan off leave my outtake fan on low and just some fans running
 

Star Dog

Well-Known Member
So maybe before my lights shut off maybe turn my intake fan off leave my outtake fan on low and just some fans running
Give it go yes, pull air from wherever its warmest.

If you take a jar of air at 15c 65% and heat it the rh% will drop though the amount of moisture hasn't changed.
Loosely speaking 14/15c 65% isn't really a humidity problem as such it's more a heat problem, if you heat the tent to 20/21c the rh% will drop.
Edit...14/15c is less than ideal 17/18c is nearing the threshold for nightime temperatures.
 

ZuuTeD614

Well-Known Member
Ok I just got home from work with my light on my temp and hunidity stay around 74 temp and 45-50 humidity with lights off temp only drops to 63 and my humidity jumped from 50 to 61 percent.
 

ZuuTeD614

Well-Known Member
I t
Ok I just got home from work with my light on my temp and hunidity stay around 74 temp and 45-50 humidity with lights off temp only drops to 63 and my humidity jumped from 50 to 61 percent.
I turned both my intake and out take fans off and both 4" fans in my tent and it staying the same. The temp went up to 65 from 63 with nothing on but humidity staying around 60
 

2com

Well-Known Member
You using HID lighting (bulbs)?

Like stardog is saying; RH is relative humidity, it's relative to the temperature. Have a look into vapor pressure deficit concept. xx% humidity being acceptable or not depends largely on the air temperature, as warmer air holds more moisture. The plants actual temp is key as well, which is why it's important to know what type of lighting you're using, as light with infrared heat will directly heat the plants.
 

ZuuTeD614

Well-Known Member
You using HID lighting (bulbs)?

Like stardog is saying; RH is relative humidity, it's relative to the temperature. Have a look into vapor pressure deficit concept. xx% humidity being acceptable or not depends largely on the air temperature, as warmer air holds more moisture. The plants actual temp is key as well, which is why it's important to know what type of lighting you're using, as light with infrared heat will directly heat the plants.
I have 2 300 watt LED lights I could sleep on them.
 

ZuuTeD614

Well-Known Member
I have 2 300 watt LED lights I could sleep on them.
I think it's because my tent is in my garage I am going to buy a nice size digital dehumidifier and put it in my garage by my tent it should do the trick I will just have it turn on when my lights turn off to keep hunidity down.
 

2com

Well-Known Member
I have 2 300 watt LED lights I could sleep on them.
Yea, so they're not adding any heat in the form of IR.
I think it's because my tent is in my garage I am going to buy a nice size digital dehumidifier and put it in my garage by my tent it should do the trick I will just have it turn on when my lights turn off to keep hunidity down.
You can add a dehumidifier, yea. It's going to remove moisture/cooler air, and pump out dryer/hotter air.
You can also just add some form of heat, and, for example, have it come on before lights out or just in time to be heating up when lights go out, to counter the spike in humidity.
You'll probably need a dehumidifier anyways though.

Good luck.
 

ZuuTeD614

Well-Known Member
Yea, so they're not adding any heat in the form of IR.

You can add a dehumidifier, yea. It's going to remove moisture/cooler air, and pump out dryer/hotter air.
You can also just add some form of heat, and, for example, have it come on before lights out or just in time to be heating up when lights go out, to counter the spike in humidity.
You'll probably need a dehumidifier anyways though.

Good luck.
Thanks man and is it safe to put a little digital heater in a tent with plants set itbat like 70 and when my lights go off that heater should stay at thr same Temps when my lights are on? And that should work?
 

Star Dog

Well-Known Member
Just make sure the heater isn't blowing on the plants and it'll be ideal.
It's worth checking out the inkbird temp/humidity hardware controllers.
 

ZuuTeD614

Well-Known Member
Just make sure the heater isn't blowing on the plants and it'll be ideal.
It's worth checking out the inkbird temp/humidity hardware controllers.
Aint that the same thing as the AC Infinity 67 controller? I have AC infinity fans I has input and out put for each fan and they work together to keep my settings?
 
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