Humidity problems upon install Humidifier

There’s a bit more to using CO2 than that, though.

@blackthumbbett Actually two! One on the very bottom other one on very top of tent

@GreenCoat I rather not do CO2 if I can

Ok, I’m confused, now. The canopy temps/rh is what we would consider the measurement taken at the top of the plants. That’s what matters, really. What is the climate at the plants’ level? Not at 20" below the light, not above the light.

Turn one of those circulating fans off…the top one.

Let the bottom fan & vents do their thing, let your exhaust fan do its thing. That circulating fan at the top will definitely come in handy during bloom, but right now it might be screwing with your dialing in.

@blackthumbbetty Yup tried that a few times no success but will try again tomorrow. Did you see my post about not ducting to my carbon filter yet. Thought that might be my problem or not?

@blackthumbbetty ok will do that now

Nah. No need for that filter til your plants are stinky.

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@blackthumbbetty No plants so I figured maybe doing 20’ below would be were the plants would be sitting because of the 400 watt MH Just a guess from a newbie

MH lights sit rather close to the canopy.

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@blackthumbbetty Ok overhead fan shut, already had the other vent closed, and I decreased the exhaust not to the lowest but 1/4 above it’s lowest setting. Will play with and see what happens. Thanks to E1 here I really appreciate all the help I can get.

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@blackthumbbetty Wow! Talk about me being way off. Glad you caught that. The hand to light trick didn’t work for me. Figured it was because of the air cooling. What do you think as a starting point. Say 10 inches?

@Dutchem
I think part of what you are experiencing that seems confusing is just the way Relative Humidity works.

Warm air holds more moisture than cold air. That’s why a cold beer/drink ‘sweats’ on a hot/humid day. The warm/humid air is cooled at the surface of the beer and becomes saturated (i.e. the cooled air cannot hold that much moisture) and creates dew at the surface.

Relative humidity (RH) really is RELATIVE…to temperature. That’s just the way it is defined. As temperature goes up, RH goes down. So if you measure the RH of a sample of air at a temperature of say, 80 degrees F and then cooled that air to 60 degrees F, the RH would increase even though the amount of moisture in the air did not change. That’s just the way RH works.

So that’s why the air at the canopy measures warm and low RH but the air above the light measures cool with higher RH. The amount of moisture in the air did not change…it just changed temperature which changes the RH. RH is DEPENDANT upon temperature. That’s the way it is defined.

Also, RH is measured as a percent, not degrees.

When the 50 degree air in your garage enters the tent and is warmed by the light inside, the RH will drop. The moisture didn’t go away. The warm air can hold more moisture than the cool air so the RH percent drops. Hope that made sense.

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@blackthumbbetty No difference that it is sucking out the air from the air cooled fixture that is now sitting on the bottom or less then 2ft from the bottom???

@poundcake LOL Am more confused now!

Keep working at it. Just tweak things here & there until you get it.

Also, give your tent about 30 minutes to equalize after you make adjustments. Changes won’t happen instantaneously.

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@blackthumbbetty Okay fan decreased to close to it’s lowest settings.

Reset the MH 400 W to 11 inches below the light. Temp now at 97 degrees and RH is at 20

So that definitely didn’t work. LOL Now put the exhaust fan in high to get the hot air out and see the new readings. Sure glad I started this before I started my seeds.

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@blackthumbbetty It definitely has to do some adjustments at 97 degrees. LOL. Thanks again. Sure getting a lot of exercise now. LOL Gives me time to take a break and do my nightly vaping

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@Dutchem
Sorry man! I’m prob am not explaining it very well. I know next to nothing about growing cannabis but I’ve dealt with regulating temp and humidity in rooms for many years. If you give it some thought you’ll get it. Just know that changing temp will change RH because RH is dependant upon temp. But changing RH won’t change temp because temp is not dependant upon RH. :slight_smile:

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@poundcake Problem is I don’t know how yet to change the RH when I already have the temps dialed in were basically I want them. So if I have the temps dialed how do get that RH I want? I have to rely on whatever temps are in the garage so I can’t change that so what are your recommendations. Or am I just not getting it? I am not the sharpest tool in the toolbox here. LOL