Any environment/dehumidifier experts that can help?

[StealthLED]

Hi all!

I'm having a issue with humidity in my room and even with a 85lt per day dehumidifier I can't control humidity very well. The problem is I can't seem to get my room below 60%, this is until the AC turns on then this will drop the humidity to the set point of 56% then the dehumidifier will turn off.

when the dehumidifier turns off and ac turns off the humidity will slowly rise, but then once the dehumidifier turns on it starts to fill the room with hot air that comes out of the outlet of the dehumidifier then the humidity will rise very fast in the room and the dehumidifier struggles to bring this back down until the AC turns on, then this will bring the humidity down. If I put a probe in front of the dehumidifier the air coming out is around 40% with a temperature of around 35-40 oC. I've tried having the dehumidifier on the ceiling I've also tried it on the floor doesn't make any difference apart from on the floor the plants leaf temperatures peek around 88oF which I don't really like, I've got 6 16" wall fans located around the room so plenty of air movement, I just can't seem to figure this problem out.

This is a new room only my 2nd grow in this room the first grow I had the same problem but I was using a industrial dehumidifier that was rated at 40lts a day so it couldn't bring the room below 65% but would top out at 75% sometimes, so I ended up replacing 2 carbon filters because the high humidity made them leak smell, I had to put 2 small dehumidifier in the room to stop this and I also got a little bud rot forming in places because of the high humidity. So I've brought this bigger dehumidifier thinking I needed a bigger one but still have a similar problem, I don't have problems with humidity peaking in the 70's like last time but I'm only 2 weeks into flower so this could change if they start drinking more.

My room is 12x8'6 with a max hight of 7ft

My AC is a split unit 120000btu

My dehumidifier is a LGR EXPERT 85LTR that's controlled by a TrolMaster - Digital Day/Night Remote Controller (BETA-1)

I have 8 plants in 2 separate rdwc systems that I veg for 5-7 weeks so they do grow big and drink a lot. Right now they're drinking a total of around 30-40lts a day.

Could this problem be that on both grows I've been using a dehumidifier that's too big for the room so they heat the room fast causing the humidity to rise? I can't see this being the problem because according to any dehumidifier supplier they will say for every litre of water the plants drink a day the dehumidifier should remove this from the room...

In the room I have a G.A.S vpd controller, the trolmaster controller that both give me the same humidity reading with around 2% difference at times.

 

[BudBogart]

Hi all!

I'm having a issue with humidity in my room and even with a 85lt per day dehumidifier I can't control humidity very well. The problem is I can't seem to get my room below 60%, this is until the AC turns on then this will drop the humidity to the set point of 56% then the dehumidifier will turn off.

when the dehumidifier turns off and ac turns off the humidity will slowly rise, but then once the dehumidifier turns on it starts to fill the room with hot air that comes out of the outlet of the dehumidifier then the humidity will rise very fast in the room and the dehumidifier struggles to bring this back down until the AC turns on, then this will bring the humidity down. If I put a probe in front of the dehumidifier the air coming out is around 40% with a temperature of around 35-40 oC. I've tried having the dehumidifier on the ceiling I've also tried it on the floor doesn't make any difference apart from on the floor the plants leaf temperatures peek around 88oF which I don't really like, I've got 6 16" wall fans located around the room so plenty of air movement, I just can't seem to figure this problem out.

This is a new room only my 2nd grow in this room the first grow I had the same problem but I was using a industrial dehumidifier that was rated at 40lts a day so it couldn't bring the room below 65% but would top out at 75% sometimes, so I ended up replacing 2 carbon filters because the high humidity made them leak smell, I had to put 2 small dehumidifier in the room to stop this and I also got a little bud rot forming in places because of the high humidity. So I've brought this bigger dehumidifier thinking I needed a bigger one but still have a similar problem, I don't have problems with humidity peaking in the 70's like last time but I'm only 2 weeks into flower so this could change if they start drinking more.

My room is 12x8'6 with a max hight of 7ft

My AC is a split unit 120000btu

My dehumidifier is a LGR EXPERT 85LTR that's controlled by a TrolMaster - Digital Day/Night Remote Controller (BETA-1)

I have 8 plants in 2 separate rdwc systems that I veg for 5-7 weeks so they do grow big and drink a lot. Right now they're drinking a total of around 30-40lts a day.

Could this problem be that on both grows I've been using a dehumidifier that's too big for the room so they heat the room fast causing the humidity to rise? I can't see this being the problem because according to any dehumidifier supplier they will say for every litre of water the plants drink a day the dehumidifier should remove this from the room...

In the room I have a G.A.S vpd controller, the trolmaster controller that both give me the same humidity reading with around 2% difference at times.

I have a 200 square foot shed and use a dehumidifier rated up to 4000 square feet and never had a problem and read that it’s okay to have an extra large dehumidifier but that an air conditioner room rating should match the room.

 

[StealthLED]

This is my average room temps and humidity lights on/off over last 3 days

 

[StealthLED]

I have a 200 square foot shed and use a dehumidifier rated up to 4000 square feet and never had a problem and read that it’s okay to have an extra large dehumidifier but that an air conditioner room rating should match the room.

My rooms half your size mate so is this maybe why im having problems because a smaller room is harder to controll? I don't know I'm lost haha

 

[StealthLED]

My AC is plenty big enough I'm only using leds mate it cools the room no problem

 

[StealthLED]

I did forgot to mention that when the lights are off I can being the room down to 50% with the dehumidifier and AC

 

[redshift75]

Have you considered pre-scrubbing the air? Thats what i do. best way to maintain an environment is controlling it before it gets to the environment itself. I just designed a whole house one for my grow tents and a controller. The problem is your trying to control the space and not the air going into the space(if that makes sense). Which because of the activity occuring is always going to be harder. Not always possible giving peoples limiting factors. Not to say its hard to control a room. But when you do there will always be some fluctuation. Smaller spaces have larger more dramatic swings than larger spaces. As less environment to change. But larger rooms things also take longer so is a trade off. The question really becomes how long the swings last. Give me a moment to read the whole post and try to get a better understanding.

if you get say a non digital humidifier. One that turns on with the power this is where a cooling and humidity controller come in handy. You can set it to shut off at X temp peak as well as humidity drops. Giving a longer time to compensate for the swings making them less dramatic. Which sounds like is going to be something in the realm of what you need to do. less dramatic more drawn out maintenance.


more than just the machines and room size and ability is the principles in which these work to achieve it. You are taking counteracting forces and pitting them against each other. it sounds like you have everything to achieve what you are wanting to do. You just need to fine tune it to your equipment a little more and all.

personally id say an 85lt per day should be more than enough. Considering 45l models are rated to do basements. Im more inclined to think there is an excessive build possibly from lack of air exchange. Id look at a recirculator system or build my own using a 4" fan to allow fresh air exchange. also known as ERV or HRV system energy or heat recovery ventilation systems. something like this
Fantech 40146 - Air Exchanger Ventilator, 68 CFM Flow Rate, 81 W

it really depends what you want to do. You could throw more at it and just try to balance out the swings through overcompensation.

whats your air change rate per hour?

 

[redshift75]

I forgot to ask

how much water is your dehumidifier pulling currently? Is it pulling its max?

To your original question i missed. yes its possible to have too large of a dehumidifier. It works in cycles. Some have "turbo" modes. These themselves can create the overheating conditions. the cycles themselves are what they are as far as temps. most of this can be balanced with Fresh air exchange.

Think of a commercial one that can make a 4000 square foot house rise 10 degrees. They dont start pulling real water out til you can feel the heat. This is where "air scrubbers" of sorts come into play. Use the excess heat to heat incoming air. You can add dryers, whatever. A bigger heat pump or desiccant dehumidifiers in actual systems. But these are all things that in principle can be scaled to any environment.

 

[Aqua Man]

Raising temps will lower humidity not raise it.

High temps will increase transpiratation rates of the plants and also evaporation from the media.

Defoliation will reduce transpiratation but at a cost of photosynthesis.

Then plain and simplest answer is get a bigger dehuey or increase air exchange.

The temporary fix would be to lower room temps and defoliate some if you can't do one of the other.

 

[StealthLED]

Thanks for the reply mate, unfortunately I don't have the space to set up another room to control the air coming in. Tbh the swings are not so bad, the temps only swing by no more than 2oC the peaks that are on the image I added is me messing around with things haha the humidity swings on average about 7% I think this is down to the controllers working range these swings are about 4 mins...

As for air exchange I use a 10" inline fan with carbon filter but I only have this running at 25% just to keep a steady flow of fresh air coming in, maybe I should increase this? Ive never thought to do this because I thought how would someone running a sealed room with no fresh air coming in manged humidity...?

I don't know how much water comes from the dehumidifier mate I have it just going to drain but I can start collecting. I'll collect for maybe 1 hour lights on then times this by 24 maybe this will give me a rough idea what water it's pulling?

 

[StealthLED]

Raising temps will lower humidity not raise it.

High temps will increase transpiratation rates of the plants and also evaporation from the media.

Defoliation will reduce transpiratation but at a cost of photosynthesis.

Then plain and simplest answer is get a bigger dehuey or increase air exchange.

The temporary fix would be to lower room temps and defoliate some if you can't do one of the other.

Cheers mate, I'm going to try increasing air exchange and monitoring water coming from the dehumidifier

 

[redshift75]

Cheers mate, I'm going to try increasing air exchange and monitoring water coming from the dehumidifier

from my viewpoint i think you have everything you need. Just need to find the right balance. I tend to over complicate things myself. But i always find less tends to be more. But some times more is more and less is less. See Confusing... C rating tends to throw me a little bit in the Fahrenheit world. But if thats all the swings are & its that short i wouldnt worry about it.

Lots of hvac stuff seems complicated. but when you look up some of the DIY projects its pretty simple to achieve. like dehumidifier with an AC . for my HRV since i have cold winters I used 6mm copper tube. Although if i were to have redone it. I would have used salvaged copper heat pipes and built a straight one where i could just use top and bottom for in/out. where the heat pipe transfers. Less efficient and more passive. I still may add it. But alot easier to source and make. Lots of this stuff is made out to be more complicated. Where it gets complicated is when you are talking wanting to spend lots of money to make specific conditions. Where you really need those techs and engineers to piece it together.

 

[StealthLED]

from my viewpoint i think you have everything you need. Just need to find the right balance. I tend to over complicate things myself. But i always find less tends to be more. But some times more is more and less is less. See Confusing... C rating tends to throw me a little bit in the Fahrenheit world. But if thats all the swings are & its that short i wouldnt worry about it.

Lots of hvac stuff seems complicated. but when you look up some of the DIY projects its pretty simple to achieve. like dehumidifier with an AC . for my HRV since i have cold winters I used 6mm copper tube. Although if i were to have redone it. I would have used salvaged copper heat pipes and built a straight one where i could just use top and bottom for in/out. where the heat pipe transfers. Less efficient and more passive. I still may add it. But alot easier to source and make. Lots of this stuff is made out to be more complicated. Where it gets complicated is when you are talking wanting to spend lots of money to make specific conditions. Where you really need those techs and engineers to piece it together.

Over complicating things is definitely me I'm a bit of a perfectionist and always like things to be 100% right

 

[StealthLED]

Just a quick update to say I've got to the bottom of the problem! At first I thought I solved the problem by turning the exhaust fan speed up but then as soon as the sun set the outside humidity climbed to 75% so this made the dehumidifier run none stop again. But the problem in fact is the trolmaster beta 6 controller that controls the dehumidifier, the sensor is completely off by sometimes more than 10% it seems to be temperature dependent on how the sensor will read, what was also throwing me off was my G.A.S vpd controller was calibrated at +6 for humidity, no idea why.. I ended up getting 2 of my caliber cigar hygrometer that I use for curing and sitting them on the sensor for the trolmaster controller and seeing a 10% difference, (I've contacted them the controller can't be recalibrated so not sure if the will send me a new one...) so in fact I've been sucking my poor plants dry with sometimes a humidity level in the mid/high 40's!

so now after recalibrating my G.A.S vpd controller and using my caliber hygrometers I've been fine tuning the room. Iv now got a rough temperature swing of around 1.5oC (2.7oF) and a humidity swing of around 8% guess I'm not going to get much better than this because of it being a small room.

I still went ahead and tested how much the dehumidifier is collecting. It nearjy filled a 25lt drum in just under 24 hours, but this is without what the AC is collecting because I forgot to drop this pipe in the drum. The plants drank 30lts in this time so I guess the dehumidifier is more than capable of doing the job!

Thanks for everyone's replys, I now have a happy room with happy plants!

 

[Anthem]

Just a quick update to say I've got to the bottom of the problem! At first I thought I solved the problem by turning the exhaust fan speed up but then as soon as the sun set the outside humidity climbed to 75% so this made the dehumidifier run none stop again. But the problem in fact is the trolmaster beta 6 controller that controls the dehumidifier, the sensor is completely off by sometimes more than 10% it seems to be temperature dependent on how the sensor will read, what was also throwing me off was my G.A.S vpd controller was calibrated at +6 for humidity, no idea why.. I ended up getting 2 of my caliber cigar hygrometer that I use for curing and sitting them on the sensor for the trolmaster controller and seeing a 10% difference, (I've contacted them the controller can't be recalibrated so not sure if the will send me a new one...) so in fact I've been sucking my poor plants dry with sometimes a humidity level in the mid/high 40's!

so now after recalibrating my G.A.S vpd controller and using my caliber hygrometers I've been fine tuning the room. Iv now got a rough temperature swing of around 1.5oC (2.7oF) and a humidity swing of around 8% guess I'm not going to get much better than this because of it being a small room.

I still went ahead and tested how much the dehumidifier is collecting. It nearjy filled a 25lt drum in just under 24 hours, but this is without what the AC is collecting because I forgot to drop this pipe in the drum. The plants drank 30lts in this time so I guess the dehumidifier is more than capable of doing the job!

Thanks for everyone's replys, I now have a happy room with happy plants!
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There most be something in the trolmaster product line that causes the humidty to read incorrectly. I am using the trolmaster hydro x control and I see the same issue or worse with the humidity readings always off, mine is even worse than yours. I often see 99 percent and 50's on a couple of inexpensive probe types. Hence I do not use it to control the dehumidifier.

 

[StealthLED]

There most be something in the trolmaster product line that causes the humidty to read incorrectly. I am using the trolmaster hydro x control and I see the same issue or worse with the humidity readings always off, mine is even worse than yours. I often see 99 percent and 50's on a couple of inexpensive probe types. Hence I do not use it to control the dehumidifier.

They've just agreed to send me a new sensor so I guess I'll still have the same problem... What controller do you use for dehumidifier mate?

 

[Anthem]

They've just agreed to send me a new sensor so I guess I'll still have the same problem... What controller do you use for dehumidifier mate?

I have a unit that has sensor and control built in

 

[StealthLED]

I have a unit that has sensor and control built in

Yeah mine does but I like to run a lower humidity when lights are off but I can only set one setting from the dehumidifier this is why I liked the trolmaster with its day and night settings

 

[Anthem]

Yeah mine does but I like to run a lower humidity when lights are off but I can only set one setting from the dehumidifier this is why I liked the trolmaster with its day and night settings

Good Idea. I did not think about that. Be careful with their CO2 sensors as well. 1 year is about what I am seeing people get out of them. If you are running high RH it might be complicating things.

 

[Goatboy]

Hey mate side question, how many watts of LED are you running in that room?
cheers