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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.
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.
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...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.
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.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.
I have a unit that has sensor and control built inThey'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?
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 settingsI have a unit that has sensor and control built in
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.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
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