Humidity issues.

willisbrow

Well-Known Member
So I’m starting my indoor grow again after a 8 year break. I have a 5.5’x5.5’ box with mars hydro fc800 and a 6” inline exhaust fan with a carbon filter. I also have a dehumidifier and some circulating fans. The box is build in my basement garage which is very humid 70%sh RH.
I’m not having issues with the lights on. Heat goes up and RH goes down. But when the lights are off my RH gets to the low 60s%.
I think what happening a that my dehumidifier is working but the exhaust fan is exhausting all the dry air that my dehumidifier made and it is sucking in the air in the garage which is very humid.
I’m not sure the size of the dehumidifier (I’m can’t remember bought it 10 years ago).
I was looking at a 50 pint dehumidifier that says it’s good up to 4500 square foot rooms
That’s what’s going on. Anybody out there growing in super humid areas have any ideas on how to get my humidity down to 35-40% during lights off?
 

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DoubleAtotheRON

Well-Known Member
That doesn't make sense. The hotter air should make more humidity due to the air being thinner, and more room for vapor molecules. Colder air is more dense, and should lower your RH. HOWEVER!.. you lights are not on burning up some of the water vapor. This is why RH rises during lights out...especially if you just fed/watered earlier that day. They are transpiring. This is just me, but I'd try to make your whole garage a lung room.
 

MICHI-CAN

Well-Known Member
That doesn't make sense. The hotter air should make more humidity due to the air being thinner, and more room for vapor molecules. Colder air is more dense, and should lower your RH. HOWEVER!.. you lights are not on burning up some of the water vapor. This is why RH rises during lights out...especially if you just fed/watered earlier that day. They are transpiring. This is just me, but I'd try to make your whole garage a lung room.
 

DoubleAtotheRON

Well-Known Member
I suppose Relative Humidity and Humidity are 2 different things.
 

PadawanWarrior

Well-Known Member
I suppose Relative Humidity and Humidity are 2 different things.
Not really. It's called RH because the water vapor in the air is dependent on temp. Warmer air holds more moisture than cold air. So if you've got a jar of 60% RH air in a Mason jar at 80 degrees and lower the temperature of the jar to 50 the RH will rise since the cold air can't hold the moisture as well. That's just my stoner explanation, :lol:
 

PadawanWarrior

Well-Known Member
Actually yes. One is actual moisture content at temp and barometric pressure relative to sea level. And relative humidity is percentage of supportable humidity or moisture under same circumstances. Really?
Technically that's pretty correct. But we only really care about RH.
 

MICHI-CAN

Well-Known Member
Not really. It's called RH because the water vapor in the air is dependent on temp. Warmer air holds more moisture than cold air. So if you've got a jar of 60% RH air in a Mason jar at 80 degrees and lower the temperature of the jar to 50 the RH will rise since the cold air can't hold the moisture as well. That's just my stoner explanation, :lol:
Same as relative oxygen level to sea level is displayed by you?


And I campaigned for your appointment to mod. OOPS!
 

MICHI-CAN

Well-Known Member
The absolute humidity can change depending on temp. That's why we go by relative humidity.

And what do you mean campaigned for me? I don't qualify anyways, :lol:.
I agree. Stick your head in your freezer and breath deeply for 2 minutes. Oxygen and humidity will help clear the head.

I posted my nominees on status. Ripped down fast. Too funny. But you and bk. More fun than a few now.
 

MICHI-CAN

Well-Known Member
So I’m starting my indoor grow again after a 8 year break. I have a 5.5’x5.5’ box with mars hydro fc800 and a 6” inline exhaust fan with a carbon filter. I also have a dehumidifier and some circulating fans. The box is build in my basement garage which is very humid 70%sh RH.
I’m not having issues with the lights on. Heat goes up and RH goes down. But when the lights are off my RH gets to the low 60s%.
I think what happening a that my dehumidifier is working but the exhaust fan is exhausting all the dry air that my dehumidifier made and it is sucking in the air in the garage which is very humid.
I’m not sure the size of the dehumidifier (I’m can’t remember bought it 10 years ago).
I was looking at a 50 pint dehumidifier that says it’s good up to 4500 square foot rooms
That’s what’s going on. Anybody out there growing in super humid areas have any ideas on how to get my humidity down to 35-40% during lights off?
Glad you know we are fools afoot of late. I do apologize. I would suggest sealing off the room and then another smaller hallway type space to dehumidify. S maller space requires less money and electric to control. My thoughts. Again apologies.
 

PadawanWarrior

Well-Known Member
Gulping slurpies is the only time my brain let's my mouth catch up!

And you know better.
Your sig reminded me of that mite to remember thread. Funny shit man.

 

MICHI-CAN

Well-Known Member
Your sig reminded me of that mite to remember thread. Funny shit man.

Still have them damn orchids. And a gnat or three. Was fun trolling with lore of ole.

And that is it?
 

willisbrow

Well-Known Member
That doesn't make sense. The hotter air should make more humidity due to the air being thinner, and more room for vapor molecules. Colder air is more dense, and should lower your RH. HOWEVER!.. you lights are not on burning up some of the water vapor. This is why RH rises during lights out...especially if you just fed/watered earlier that day. They are transpiring. This is just me, but I'd try to make your whole garage a lung room.
I wouldn’t say my RH rises when lights go off. My garage has a RH of around 70% and so does my grow box with nothing running(lights and dehumidifier) And when the lights go ON and the RH drops to 40% or so. Then when the lights go off my box goes back to the RH of the garage it’s in.
so…. The rh drops with the lights and heat on and goes back up when the lights go off.
 

DoubleAtotheRON

Well-Known Member
I wouldn’t say my RH rises when lights go off. My garage has a RH of around 70%. And when the lights go ON and the RH drops to 40% or so. Then when the lights go off my box goes back to the RH of the garage it’s in.
so…. The rh drops with the lights and heat on and goes back up when the lights go off.
This is totally different than what you said in the first place.
 
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