saw quite a few cool air mist humidifiers like from Vicks that are small like a vaporizer I saw these online they’re about the size of a vaporizer there cool mist humidifiers
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I use one of these in my tent right now! I think my sister got it off Amazon for $20 years ago. It works great- but drains the 2L tank in about a day. Actually cools the tent a bit too.
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Right on i think i may get one also just in case you never know
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Yeah, I noticed that too. When its running it drops the tent temps down a good bit. I guess thats why they are called ‘cool mist’ 
I should have guessed that up front. All those micro droplets absorb heat energy as they evaporate.
I still working on this whole thing. Ive been going over my tent sealing up leaks. I havent worried too much about them because Im only growing autos, so light leaks are no big deal. Plus, most of the time Im more concerned with cooling the tent, so having more air flow - even in the form of leaks - was actually good.
Ive decided Im going to have to have two different operating modes. One where I have young plants that need added humidity, and the second where I need more cooling, and better air flow. The two dont seem to mix well at all. I wont be able to really tell how well this is going to work until next week. Thats when the humidity controller will be here. For now all I can do it turn on the mister and leave it running for a while and ass what happens. I was sure I had another sonof somewhere, so I could put it on a timer, but I cant find it so far.
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So, it looks like this particular fogger puts out just enough mist to get me to 50%-55%, but it needs to run pretty much full time to do it. And every time the cooling fan comes on the level drops back to the hi 30’s.
I have it on a timer now running 16 minutes ON x 2 minutes off and its holding in the 45% range.
Im worried about how long these things will last running 24/7. I was really hoping it would work at 50% duty cycle or less.
So - I either need to partition off the lower section of the tent with a transparent barrier (no), or buy two more of these (dont want to), or build a bigger humidity dome that will fit growing young plants until they get much larger, and feed this into it.
I dont like any of those options, but the larger dome is probably the way Im going to go - maybe. I dont think I have any clear plastic containers that are big enough, but I will keep looking. I may have to make a frame out of PVC pipe and wrap it in clear cellophane. I have some plastic drop cloths, but they are not transparent enough.
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I decided the dome idea wouldnt work. It would need to partly cover my access hatch to get into the root chamber.
Then I had an idea - I could use my scrog screen frame to partition off the lower section of the tent. I put the frame in place, then covered it in plastic wrap - which was a pain in the you know what. I then sealed up the small gaps around the edges more or less and tried it out using the humidity controller I linked to above.
Its working much better now. Not as well as I hoped, but this may work long enough to get the babies grown up a bit.
I set the controller to 60% cut off with 10% hysteresis. It takes right at 1 minute 8 seconds to go from 50% to 60% and almost exactly 1 minute to drop back down. So its running at around 50% duty cycle.
This is good because Im ready to put two new very very young babies into the system. We will see how long this lasts. Fortunately, the fogger came with two replacement elements.
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Well, this is working but its far from ideal. The basic problem is that this single fogger is just too small for my space, plus my tent is a sieve with extra large holes as far as keeping humidity inside.
I had to basically convert the entire lower 1/4 of my tent - which in my case is about 7.5 cubic feet of my tent - into a humidity dome. I had to really hunt for air leaks and work at getting it sealed up as well as I could. The system still cycles about every 1.5 minutes. I have it set to come on at an RH of 55% and cut off at an RH of 75%. The growing zone stays right around 60%-65% on average. Its using about 1.5 to 2 quarts of water per day, so Im still loosing a lot of humidity into the rest of the tent and/or the grow room.
This also makes it a pain to check on and work on the plants, but its workable.
What I ended up doing was putting the fogger into a 1 gallon bucket with a lid with two holes cut into it. One is for the fog to come out. I made a small deflector out of thin foam sheet to direct the mist horizontally as it comes out - basically a 90 deg elbow made from foam. I would have used a 2" PVC elbow but didnt have any on hand. I put a small computer fan over the other hole blowing air into the bucket. That seems to distribute the fog around the tent better and helps the humidity climb faster when it turns on.
Bottom line, this is a cheap option that can be made to work for a small space, but its far from ideal.
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Did you find a solution here? Now that we’re into winter it’s starting to dip below 40% in the house, keeping the tent closer to 50-60 is a battle, I’ve filled my 2L humidifier twice today. I haven’t thought of a better solution. What I may do is use an add on whole home humidifier to run off the water line. It’s like a dish, with a rotating sponge, essentially just giving the water a lot of contact with the cold air returning to the furnace. If you were determined to you could DIY it, I’d think.
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This is similar to what I use to control a 28x32 room might run 5 min every hour to maintain my humidity .
Forgot to add you can make it rain if you wanted when using a big enough pond fogger and bathroom fan
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taking control of humidity should be somewhat slower and stable process, and with that kind of difference between inside and outside RH, i have a feeling it will have to be able to be on all the time. misters are made for humidifying rooms, not tents afaik. sealing off your tent and starting humidifier before intake of new air into your tent should help overcome some of the oscillations. if youre using arduino and relay, you can check out PID library: https://github.com/br3ttb/Arduino-PID-Library it is a controlling process that is used to predict and smooth oscillations that youll have (its used in linear, closed systems, but it may help with smoothening nevertheless, esp when dealing with hard hits like turning your cooling fan on) it is harder to get from 35 to 40 % RH than from 60 to 65 % from my own tests. @ShiskaberrySavior what is the RH of the air you get inside your room? what kind of oscillation can your setup handle?
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ESP 32 controller is the route I’m going, programmed in Arduino. So that actually helps quite a bit!
I am reworking the air flow for the tent, I am guessing my issue was over blowing. I am adding a speed controlled fan to run constantly at low speed. Coincidentally, since I don’t want it in my tent, I am building space for my little humidifier in a mdf box, with filtered air intake for the tent (20” furnace filter) so I may test out a staggered timing instead before buying the speed controller, we’ll see. It for sure needs less ventilation. I don’t know what the fan is rated- but it blows harder than my fan rated at 88CFM. And mind you, I’m growing in only a 3’x3’x6’ tent. So at least cycling the entire tent every minute. So basically, you know, I missed the obvious.
Ah, yesss, 15-bit PWM for the smoooothest rideee… Then search github for esp32 version of that lib, there should also be autotune one… You can save yourself a lot of time of testing and debugging with good insulation, leave esp for things you cannot manage… And ofc, share some pics of your device!
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For sure- insulation is my issue. My tent sits alone in the basement, nothing but cold dry air around it. I had to add a space heater for night time, temperature difference was getting to be an issue with humidity I thought. Well, yes temps are more stable now, it didn’t help humidity worth. Damn. But since I intend to code the controller mostly for sensors, to data log, it’s actually not much harder… I think. I should note I am learning Arduino C++ for this, I am not a programmer at all. I’ve made little blinky light code, but nothing serious. Heavily relying on GitHub lol.
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If you go to Good Will, you can usually find one trillion humidifiers for sale for 5 bucks or less. People have a baby, buy them, and then donate them. You can cannibalize them for parts and make your own DIY ultrasonic mister or you can use them as is. You can get the air exchange just right and keep it at a constant humidity with a humidifier running, it just takes some trial and error to dial in the exchange
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If youre into science of how and why, here is a good explanation of what relative humidity is and how it changes relative to temperature…
" Within a pool of liquid water, some molecules are continually escaping from the liquid into the space above, while more and more vapour molecules return to the liquid as the concentration of vapour rises. Finally, equal numbers are escaping and returning; the vapour is then saturated, and its pressure is known as the saturation vapour pressure, e w . If the liquid and vapour are warmed, relatively more molecules escape than return, and e w rises. There is also a saturation pressure with respect to ice. The vapour pressure curve of water has the same form as the curves for many other substances. Its location is fixed, however, by the boiling point of 100 °C (212 °F), where the saturation vapour pressure of water vapour is 1,013 mb (1 standard atmosphere), the standard pressure of the atmosphere at sea level. The decrease of the boiling point with altitude can be calculated. For example, the saturation vapour pressure at 40 °C (104 °F) is 74 mb (0.07 standard atmosphere), and the standard atmospheric pressure near 18,000 metres (59,000 feet) above sea level is also 74 mb; thus, it is where water boils at 40° C.
The everyday response of relative humidity to temperature can be easily explained. On a summer morning, the temperature might be 15 °C (59 °F) and the relative humidity 100 percent. The vapour pressure would be 17 mb (0.02 standard atmosphere) and the mixing ratio about 11 parts per thousand (11 grams of water per kilogram of air by weight). During the day the air could warm to 25 °C (77 °F), while evaporation could add little water. At 25 °C the saturation pressure is fully 32 mb (0.03 standard atmosphere). If, however, little water has been added to the air, its vapour pressure will still be about 17 mb. Thus, with no change in vapour content, the relative humidity of the air has fallen from 100 to only 53 percent, illustrating why relative humidity does not identify air masses."
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I use a cheap $29 cool mist humidifier from wally world by equate ive had it for a month and seem to be maintaining %53
Peaceoutand stay safe
Yo, I feel like I have not seen you on the aeroponics threads, how long have you been doing the AAA?
Hey, is that 28x32 feet or inches?
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That’s feet it will pump out over 5 gals of water in a 24 hr period if needed . Mine was built using a single pond fogger approximately 6 inches around with a external power box stepping power to 240 volts .
I also used a bathroom ceiling fan vs the small fan shown in the video which allows it to really fog fast .
I found a video showing the proper mister I used below .
Onward through the fog !
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Thats awesome, i wouldnt believe it was that powerful, seems like a no brainer…
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