Humidity problem

Dr. Frescho

Dr. Frescho

Member
Hi you all, so i've just switched to 12/12 for flower mode, but i can't keep my humidity below 65% even tho i have a dehumidifier, an exhaust fan (187m3) and a carbon filter (max range 150m3).
So what do you suggest, should i change my exhaust fan or carbon filter? Should i take a carbon filter with a max range of 300m3 or an exhaust fan of 300m3 or both?
I just need to lower this humidity to 45% or 50% for optimal humidity for flowering.
Also i wanted to install an intake fan (80m3) that i already had ,but sadly the growroom becomes a balloon,meaning there's more air going in than air going out....
So what should i buy to increase air exhaust?
 
Dr. Who

Dr. Who

Well-Known Member
Describe the area you grow in please.
Tent in a room?
Room? Area in the basement?

Where is the dehumidifier?
What is the RH of where your intake comes from?
 
Dr. Frescho

Dr. Frescho

Member
Dr. Who said:
Describe the area you grow in please.
Tent in a room?
Room? Area in the basement?

Where is the dehumidifier?
What is the RH of where your intake comes from?
Click to expand...
My growroom is a 80x80x180,the dehumidifier is inside the grow room.
The area of my room is 10 square meters,with a base RH of 57/60%....

mmmh maybe that's the problem the base humidity OUTSIDE the growroom
How can i lower the room humidity? I have only one window.
 
Dr. Frescho

Dr. Frescho

Member
Couch_Lock said:
A stronger inline exhaust fan, save current one as a backup. MORE CFM exhausting!
Click to expand...
That's what i was thinkin too,but should i upgrade a carbon filter too? current one is only 150m3,if i buy i a new excractor i'll take one with a capacity of 300m3,i dunno if it's enough for a filter like that
 
thumper60

thumper60

Well-Known Member
Dr. Frescho said:
Hi you all, so i've just switched to 12/12 for flower mode, but i can't keep my humidity below 65% even tho i have a dehumidifier, an exhaust fan (187m3) and a carbon filter (max range 150m3).
So what do you suggest, should i change my exhaust fan or carbon filter? Should i take a carbon filter with a max range of 300m3 or an exhaust fan of 300m3 or both?
I just need to lower this humidity to 45% or 50% for optimal humidity for flowering.
Also i wanted to install an intake fan (80m3) that i already had ,but sadly the growroom becomes a balloon,meaning there's more air going in than air going out....
So what should i buy to increase air exhaust?
Click to expand...
stop exhausting lights out let the dehuy work,only exhaust when temps need to come down.
 
Dr. Frescho

Dr. Frescho

Member
thumper60 said:
stop exhausting lights out let the dehuy work,only exhaust when temps need to come down.
Click to expand...
So i should stop the exhaustin fan only when lights are out?
Correct me if i'm wrong, but from what i've learned so far is that the exhaust fan should always be on....
If not it promotes mold and diseases...
 
Dr. Who

Dr. Who

Well-Known Member
Dr. Frescho said:
My growroom is a 80x80x180,the dehumidifier is inside the grow room.
The area of my room is 10 square meters,with a base RH of 57/60%....

mmmh maybe that's the problem the base humidity OUTSIDE the growroom
How can i lower the room humidity? I have only one window.
Click to expand...
Hmm you mean 10 square meters or about 354 sq ft. of room space?

How many plants?
How big a dehuy?

How are you controlling temps? What temp does it (room) run at? - lights on average please.
 
Dr. Frescho

Dr. Frescho

Member
10 square meters,2 plants,the dehumi has a capacity of 350ml, and i'm controlling temps with 2 heaters (each 150w) plugged in a temperature controller device.
My base room outside the growbox it's 18 degrees , in the growroom is 28 degrees durin lights on, and about 22/20 degrees during lights off.
I'm using a 270 w LED PAR+ from diyleduk .

But except this, can someone please explain to me if i should turn off the exhausting fan, timer it or leave it always on...
Cause at this point i'm making a lot of confusion about it, some say i should leave it on others no...
 
OzyM8

OzyM8

Well-Known Member
Work out what your plants uptake of water is per day and I think you’ll find the 350ml dehu is way to small. Plants transpire almost all of the uptake.
If you’re doing continuous air exchange, and you’ve size your fans correctly, I’d say you’re more over going to be sitting at the ambient air humidity anyway and the 350ml dehu isn’t doing much.

Also you need a higher capacity exhaust fan than intake if you want negative pressure, otherwise you’ll have positive pressure like you have “tent ballooning”

There’s way to much to explain in a simple post. Start researching, there’s plenty of info available on the net.
 
Dr. Frescho

Dr. Frescho

Member
OzyM8 said:
Work out what your plants uptake of water is per day and I think you’ll find the 350ml dehu is way to small. Plants transpire almost all of the uptake.
If you’re doing continuous air exchange, and you’ve size your fans correctly, I’d say you’re more over going to be sitting at the ambient air humidity anyway and the 350ml dehu isn’t doing much.

Also you need a higher capacity exhaust fan than intake if you want negative pressure, otherwise you’ll have positive pressure like you have “tent ballooning”

There’s way to much to explain in a simple post. Start researching, there’s plenty of info available on the net.
Click to expand...
Ok dude, i bought a 300 m3 fan extractor that will release air outside the room in which is the growroom,350ml should be fine for a 80x80x180, also because a dehumi of 1/2 L would be too big for a growroom like this one.

And finally i'll add the intake fan that should improve airflow and reduce humidity,the intake fan (80m3) will take air directly from the room.

The thing is i already looked for it, but in this case i found very different ideas about the exhaust fan schedule... If you could please link me a guide about it you'll have my deepest thanks :,)
 
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