How I control VPD

SuperNice

Active Member
After struggling with this for months, I have hit on a solution that seems pretty close to perfect.

I have an 8x8 sealed tent.
I am running a Whynter ARC-14S set to 75 degrees (it's really at 69, but it translates to 75 average in the tent).
I have a ALORAIR Storm LGR Extreme dehum that runs constantly - set to continuous.
I have an Ideal-Air Commercial-Grade Humidifier GSH75, humidifier. It runs on a smart plug.
I am using SensorPush sensors. SensorPush HTP.xw Wireless. I have two, I calibrate one while the other is working and swap them back and forth.

I write software for a living (see screen shot). I wrote it using Visual Studio C#, but I think you could pull this off in Access.

So. The sensor reads the temperature. My software calculates the humidity range for that temp for the VPD range I've assigned, hi and low.
The AC keeps it close to 75 most of the time.

I live in the South, and you guys know what kind of summer we have had.
Hence the handful of failures and the larger humidity range showing. But these are momentary spikes.
And I'm also convinced that the Good Lord wants to remind me I am not perfect and never will be.

The Dehum, as I said, runs constantly. When it gets close to the high VPD range (1.1 in the screenshot), the humidifier kicks in long enough to lower it to the lower VPD (.9 in screenshot).

Yes, that's right, I run the Dehum and the Humidifier at the same time. Seems stupid. Nope. More costly to stop and restart the dehum than it is to leave it running. That humidifer is a big fogger. Doesn't run long, ever.

Then the process starts over.

The humidifer is on a timer, actually. It turns on the smartplug, and turns on a timer that runs it long enough to force it to the lower range (the time it runs to do that is a setting, of course, as it may vary).

Any questions?
How is that alorair Dehu holding up? I have the sentinel hd55 model on the way.
 

linky

Well-Known Member
I have/had 2 lgr extreme's, one failed and Alorair told me about an issue in some environments where this model can corrode and leak out the refrigerant. Not sure if that is what happened to mine, but it was giving the refrigerant leak error code. They replaced it with the Sentinel HDi100, very happy with that one so far, have had the sentinel for 1.5 years now and the LGR for about 2.5 years. They pull out a lot of water. I had originally bought the 2 LGR's around the same time, within a few months of each other.
 

SuperNice

Active Member
I have/had 2 lgr extreme's, one failed and Alorair told me about an issue in some environments where this model can corrode and leak out the refrigerant. Not sure if that is what happened to mine, but it was giving the refrigerant leak error code. They replaced it with the Sentinel HDi100, very happy with that one so far, have had the sentinel for 1.5 years now and the LGR for about 2.5 years. They pull out a lot of water. I had originally bought the 2 LGR's around the same time, within a few months of each other.
Good to hear the customer service is up to par. Excited to see what this hd55 can do.
 

Stumay111

Active Member
@Stumay111
Cool stuff, man. I love to see any of this type of thing. I wish I had the skills.
Anyway, this place has more assholes than anything else. Please don't let it affect your want to share your ideas and stuff.
Fear not. I believe all weed and knowledge of same should be free and plentiful.
We are basically a giant research team.
 

Stumay111

Active Member
I have/had 2 lgr extreme's, one failed and Alorair told me about an issue in some environments where this model can corrode and leak out the refrigerant. Not sure if that is what happened to mine, but it was giving the refrigerant leak error code. They replaced it with the Sentinel HDi100, very happy with that one so far, have had the sentinel for 1.5 years now and the LGR for about 2.5 years. They pull out a lot of water. I had originally bought the 2 LGR's around the same time, within a few months of each other.
Wish Id seen this first!
 

watsongreenthumb

Active Member
very interested in your sensor setup, I have been looking for a better way to automate my environment than what is out there, both from a cost effectiveness standpoint as well as functionality. I have some basic coding knowledge but my bro is a software engineer and probably going to write most of the code, although will check out your program for sure. we were planning to use a raspberry pi, for the readily available sensors and whatnot, what are your thoughts on the sensors you used? are they difficult to calibrate therefore needing two? any info you could give me would be great, your the first person I have seen to really accomplish this in an in depth manner. the dream would be to build a system that could both control the environment and a dtw irrigation system, with the ability to adjust fertigation strength and ph based on runoff sensor readings to hit a target runoff ec and ph. Thats down the road though, for now we are just looking to control the environment (and co2) as well as log all the data. controlling a minisplit through the IR port like trolmaster does is one of the first big hurdles I envision.
 

Stumay111

Active Member
very interested in your sensor setup, I have been looking for a better way to automate my environment than what is out there, both from a cost effectiveness standpoint as well as functionality. I have some basic coding knowledge but my bro is a software engineer and probably going to write most of the code, although will check out your program for sure. we were planning to use a raspberry pi, for the readily available sensors and whatnot, what are your thoughts on the sensors you used? are they difficult to calibrate therefore needing two? any info you could give me would be great, your the first person I have seen to really accomplish this in an in depth manner. the dream would be to build a system that could both control the environment and a dtw irrigation system, with the ability to adjust fertigation strength and ph based on runoff sensor readings to hit a target runoff ec and ph. Thats down the road though, for now we are just looking to control the environment (and co2) as well as log all the data. controlling a minisplit through the IR port like trolmaster does is one of the first big hurdles I envision.
My only regret is not going with a split.
After a lot of experimentation, as I said, I'm running the AC set to about 72 and the dehum continuous. The humidifier is the only thing I am controlling (besides CO2) with my smart plugs.
I actually had an irrigation setup but I only used 1/4 line and should have used 1/2. It also would have been controlled by the smart plugs.
I'm using Kasa smart plugs, but I am considering switching as the Kasa seems to wear out.
 

visajoe1

Well-Known Member
In my experience with VPD management in a personal grow, this boils down to ability to maintain temp and humidity levels within acceptable ranges. This doesnt need to be perfect every second of every day; nature isnt.

The variable I find needs most attention is humidity. Raising or lowering in response to temperature is simplest solution for me. Best of luck
 

Astral22

Well-Known Member
Some nice equipment there. I was thinking of running a similar setup on a smaller scale. I have a question that might sound stupid, but it would be a useful info for me to plan my setup.

Since your AlorAir dehumidifier has an automatic humidistat controller, can you set it at 50% RH and let it run on it's own to keep it at that range all the time? What's the drawback to this?
 

SensibleSensimilla

Active Member
Nice project. For those interested in automation like this, without extensive coding/software development knowledge required, you should look into Node RED (https://nodered.org/).

Node RED running on a Raspberry Pi, combined with a capable temp/hum sensor and a few smart plugs, can achieve much of the same automation functionality without a high knowledge/experience barrier to entry. It will not be an effortless project, but it is well within the grasp of someone determined to replicate the functionality of an expensive, ready-made/off-the-shelf, grow room controller.
 

Stumay111

Active Member
Care to share a link to the repo? I'd like to check out the VPD control algorithm logic.
I can't swear this will work, and that's a very old version, but that might help.
The logic is simple. Read the sensor. Act accordingly. In my current setup, all that involves is turning a humidifer on or off.


 

karn.k

New Member
After struggling with this for months, I have hit on a solution that seems pretty close to perfect.

I have an 8x8 sealed tent.
I am running a Whynter ARC-14S set to 75 degrees (it's really at 69, but it translates to 75 average in the tent).
I have a ALORAIR Storm LGR Extreme dehum that runs constantly - set to continuous.
I have an Ideal-Air Commercial-Grade Humidifier GSH75, humidifier. It runs on a smart plug.
I am using SensorPush sensors. SensorPush HTP.xw Wireless. I have two, I calibrate one while the other is working and swap them back and forth.

I write software for a living (see screen shot). I wrote it using Visual Studio C#, but I think you could pull this off in Access.

So. The sensor reads the temperature. My software calculates the humidity range for that temp for the VPD range I've assigned, hi and low.
The AC keeps it close to 75 most of the time.

I live in the South, and you guys know what kind of summer we have had.
Hence the handful of failures and the larger humidity range showing. But these are momentary spikes.
And I'm also convinced that the Good Lord wants to remind me I am not perfect and never will be.

The Dehum, as I said, runs constantly. When it gets close to the high VPD range (1.1 in the screenshot), the humidifier kicks in long enough to lower it to the lower VPD (.9 in screenshot).

Yes, that's right, I run the Dehum and the Humidifier at the same time. Seems stupid. Nope. More costly to stop and restart the dehum than it is to leave it running. That humidifer is a big fogger. Doesn't run long, ever.

Then the process starts over.

The humidifer is on a timer, actually. It turns on the smartplug, and turns on a timer that runs it long enough to force it to the lower range (the time it runs to do that is a setting, of course, as it may vary).

Any questions?
I have question. I have on/off Dehu control and AC Inverter type. I plan to have minimum of 2 Dehu units, plan to run one of them 24x7 and the other on/off which mean it will fluctuate a bit.

Do you think it work ok, If I measure VPD and adj temperature (to compensate RH swing) so I get constant VPD?
 
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