So automation is simple to me because it is part of my job as an HVAC technician. I have the AC Infinity Pro 69 controller actually two setups with the same controller. I’m starting my first grow and I’m wondering how I control VPD. I figured out the auto functions and timer functions but I have not figured out what devices I need to control to maintain VPD. I have exhaust fans humidifiers circulating fans the whole nine yards . I can also control the humidity in my grow room . I have filtered intakes piped into my grow tents from the room Thank you to all
I’ve always ignored VPD and instead run >50% RH in veg and <50% in flower.
You can probably set your target temp and RH and see how close you can get to the ideal VPD, but it would be a challenge and I’m not sure that the time, money, and frustration would actually make any substantial difference in your weed quality.
Inkbird makes great RH and temp controllers, but you still have to control temp and humidity separately to achieve your goal.
I would spend my time mastering the basics of growing (soil, lighting, pH, PPM, watering…) before chasing VPD.
Airflow is the easiest and cheapest way to control temp and RH.
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I couldn’t agree with @MidwestGuy more. Some of the most respected growers on here live(d) in areas that ideal VPD was unattainable and still grew incredible bud.
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lol. Like in the Midwest where it is 98F and 82% RH right now.
Sitting here waiting for the afternoon pop-up thunderstorms to appear.
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supposed to have some of those coming my way too. So far it’s just 35mph wind.
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Yeah, chasing VPD seems useless and frustrating. I find it not very cooperative…i open my tent to feel the leaves and thats my VPD.
If i start staring at my pro 69 controller for too long my eyes go crossed and i work myself up into a frenzy…forget it
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Ditto, chasing VPD numbers will drive you insane.
Words to grow by 
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VPD chasing is expensive. Ask me how i know… i quit chasing it and like @MidwestGuy mentioned, set up your targets and try your best to hit em. Weve got 100°F plus temps and my rooms are cooking and even the acs cant keep up. Best i can get is around 82 with 100 plus outside. Humidity i try to keep around 50.
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I quit chasing it. It is what it is. Have no issues myself growing not being perfect. I am pretty sure God doesnt use controllers.
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While I too stopped chasing VPD, I do monitor it via my Pro 69 and try to adjust temp or RH if really needed. But originally I was all about, OMG it has to be perfect. Ok, maybe I didn’t get 100% over it, but chasing was too much work. Keeping my temp and RH under control is where the key is in all that mess.
And be sure to calibrate your controller from ACI. Once I did and dialed it in, the VPD stopped jumping like crazy.
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How does one calibrate the pro 69 contoler?
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I do this, and it is working for me. I set my intake and exhaust fans for auto temp mode at 80. This keeps my tent +/- a degree of that during lights on.
I run a dehumidifier in my lung room and set it to make sure it is a few % lower than I want my tent. For example right now I am in early veg, so I have it set at 60%. Then I use my humidifier set to VPD mode, and simply set my target VPD.
I am using the Advance features for this, but only so I can have other programmed settings. I can get my VPD just about perfect this way.
Currently I am set for a VPD of 0.9:
Good luck!
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I too use the advanced programming. It just makes life so much easier. I didn’t set for VPD, but do have an alert set if it goes outside of .08-1.5.
I’m flowering.
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Set the leaf temp offset, humidity, and temp if needed. I always use two or three hygrometers and a laser temp gage to check anywhere I need with precision.
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Yes, i have done that with the app settings but i thought there was another overall calibration.
I seem to remember that there was another calibration for the app. I was smoking alot when this happened so i might be confused a little but, i can remember all my readings changing rapidly as i was trying to calibrate it…?
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what humidifier are you using? AC I?
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Yes. The smaller one. T3, I think is the model number.
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@Newt just got one…need the 69pro…soon!
have you had issues with hose dripping? using the hose?
getting the big one for my veg tent.
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It does drip. So I extended the tube down so that it sits just inside a mason jar. When the jar needs emptied, it goes right back in the humidifier. 
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i had, feed before last, a huge puddle in my tents tray…
i adjusted the hose…now only a drip here and there…still though…a pain.
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