OzyM8
Well-Known Member
100%....well expressed.
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Killer info for setting up a CO2 equipped grow room!
- Thread starter OldMedUser
- Start date
Nizza
Well-Known Member
about the dual hose ac unit and running minisplits in the winter... It is possible to locate your condenser INSIDE, in a different part of the house, and re-use that heat. Just be sure to have a drain setup for the condensing unit as well!I'm still planning on setting up a sealed grow room. Need a dual hose portable AC unit as it's too cold here for a mini-split in the winter. The AC unit does dehuey duty as well and costs the same as the same BTU mini-split. Single hose unit uses room air to cool it's parts but the dual hose draws outside air for that and sends it out the 2nd hose so no room air is lost. Hard to find in winter and I don't have a spare G-note atm either.
Not sure how much longer we'll be living here so not that eager to get deeper into this right now. Already spent around 3G on gear the last 3 years.
New 8" inline fan and adapter on the way via amazon. The VISA card has taken quite a beating the last little while.
why waste all that energy, as long as you wouldnt have to relocate that condensor in the summer.
In that case it might even be possible to run two units, one for summer, one for winter depending on budget and cooling costs in the winter
If its so cold outside why not exchange cold air from outdoors?
LarsVegasNirvana
Well-Known Member
Metric degrees are way way bigger. I seriously doubt you have a -2C LST.
OzyM8
Well-Known Member
Yes, they are. I think you may have missed the point of my post though and gone straight to nit picking assuming I said I had a LST of -2C, which I did not. If you’re interested, then this is what I’ve got right now at week 4 veg lights on.
Ambient temp swing 26.5-27.5C
Average LST at canopy 26.3C (rough average)
RH: 62-66% max set at 68%
PAR 600ish
CO2: 650 target, low set 450, and I get about 50-80ppm overshoot.
Obviously temp, RH, CO2 changes a bit during a quick timed vent, then resets.
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LarsVegasNirvana
Well-Known Member
I think you've missed the point of my post. You might as well be calculating your desired humidity in millionths of a percent, because you have no ability to actually control anything at that resolution. LST is very close to ambient in high PPFD and low VPD conditions. So low that it's within the margin of error of the sensor. It literally means nothing. It's lost in the noise of constant errors in your system. You can't say it's good to aim for something if you have no ability whatsoever to aim for it. For all you know when you add or subtract that 2%RH you might actually be counter-productive because you already have an error in that direction from your sensor.
OzyM8
Well-Known Member
Agreed, who wouldn’t calibrate their sensor/s against a known value though? There’s a lot of variables to consider, and that in itself is knowledge.
LarsVegasNirvana
Well-Known Member
The best humidity sensors in the world are incredibly inaccurate. You can calibrate it and the next day it's wrong again. If you have two sensors they'll start to diverge almost instantly.
It's kind of like in chemistry class when they teach you the gas equations, they teach you a simplified version that doesn't include the van der walls forces because you have no equipment in a college chemistry classroom to measure such tiny forces. They literally just assume that they don't exist and teach it as if it didn't exist.
Now if you're using HPS lights then I'm sure you've got like a 15%RH difference due to LST and that would totally be worth calculating.
OldMedUser
Well-Known Member
But the whole idea of a sealed room is to prevent exchanges of air. I used to get air from outside but in winter it's too cold and too dry then in summer too warm and still a little too dry. Drawing my air from the larger area of the basement is a lot more even in temp and rh tho it does go from about 40 - 68F but that's a lot better than -40 - 95F.
LarsVegasNirvana
Well-Known Member
You can buy a heat exchanger to cool your interior air with exterior air without actually mixing them together. Most people use them to keep the heat inside their homes and still achieve air exchange, but you could do the opposite and seal your air up and dump your heat.
LoganGP
Active Member
The info here on these forums are worth there weight in bud! 
. You guys have some very resourceful information here. Looking forward to getting my new grow shed dialled In and tweeked.
I will be Shooting for
*800ppm co2
*82f ambient
*65%RH
* 79f lst
According to the calculator in previous post that puts me at a 1.3vpd which looks to be target. Before reading this post today I was running 72% RH and that puts me at a 1.0vpd. Looks to be a fair difference as per vpd chart.
. You guys have some very resourceful information here. Looking forward to getting my new grow shed dialled In and tweeked.I will be Shooting for
*800ppm co2
*82f ambient
*65%RH
* 79f lst
According to the calculator in previous post that puts me at a 1.3vpd which looks to be target. Before reading this post today I was running 72% RH and that puts me at a 1.0vpd. Looks to be a fair difference as per vpd chart.
smokeymcpotterton
Well-Known Member
It's not exactly a new concept... I remember 15-20 years ago growers were telling me about co2 being the 'missing link' to killer grows.CO2? Wow, you folks are pretty hard core if you are venturing into that kind of stuff. It's too bad you couldn't somehow suck air in from outside, or even from within your house (or wherever your setup is). Plenty of CO2 out there for sure. Just ask the climate change nuts.
The only CO2 I dealt with was for carbonating my beer
I'm sure it isn't. Still, there's a LOT of CO2 available for free; just have to figure a way get it into the grow space.
I just came up with an idea. Set your grow space next to a brewery. They spew a shitload of CO2 from fermentation. Just pipe it in
Keesje
Well-Known Member
Grow in a city with heavy traffic. Also high CO2.I just came up with an idea. Set your grow space next to a brewery. They spew a shitload of CO2 from fermentation. Just pipe it in
smokeymcpotterton
Well-Known Member
Or just split off your dryer exhaust... Air has about 700 to 800 ppm, Half of the 1400 to 1500 that growers ideally want.I'm sure it isn't. Still, there's a LOT of CO2 available for free; just have to figure a way get it into the grow space.
I just came up with an idea. Set your grow space next to a brewery. They spew a shitload of CO2 from fermentation. Just pipe it in
In this article, https://medteknutrients.com.au/co2-enriched-hydroponic-growing/, the author states that "Even though plants produce about ten-times as much oxygen during the day as they consume at night, the night-time consumption of oxygen by plants in confined spaces (high plant mass per volume of space) can potentially create low oxygen conditions for respiration at night. As plants consume oxygen and release Co2 during the night, in a well-sealed grow room this potentially creates a deficit of oxygen - oxygen that is needed by the plant for respiration.
Basically my question is, in my case, I run about 1000ppm in my sealed room, and during lights off, even though the tank is shut off, my monitor reads ~1500ppm. I was wondering if this was detrimental to the health of my plants.
Basically my question is, in my case, I run about 1000ppm in my sealed room, and during lights off, even though the tank is shut off, my monitor reads ~1500ppm. I was wondering if this was detrimental to the health of my plants.
TintEastwood
Well-Known Member
Venting.
Keesje
Well-Known Member
I doubt if that can happen.
First reason is that there is so much O2 in the air.
Let's say your room is 2 meter x 2 meter x 2 meter. That is 8000 liters of air, of which about 20% is O2. That is 1600 liter of oxygen in gaseous state. So that is 1.6 M3. It will weigh 1,6 x 1.4 kilo = 2.24 kilo of O2.
No way that plants that can fit in such a room will absorb this amount of O2 in one night.
Second reason is that a room is never completely sealed. And O2 will slip through the tiniest hole.
The article of medteknutrients is nice, but there is also some pseudo-science in it.
Higher CO2 levels are not dangerous to plants (CO2 poisoning is bro science. Yes, it can happen, but then you need extremely high values. Same with people)
Perhaps you still know this 'fact' from the past that one should not have plants in the bedroom, because it would consume all the oxygen.
It was total nonsense. An average house plant (not cannabis) would absorb about 50 ml of oxygen per night. Even if you have a small bedroom of about 2 x 3 x 2.5 meter = 15 M3. 3 M3 of that is oxygen. That is 3000 liter = 3,000,000 ml of O2.
@SourDeezz Your CO2 ppm is so high because your CO2 will stay mainly in the room. The plants produce CO2 in the night.
If you take your CO2 controller and go in a forest at night, you will also measure a higher amount of CO2 as during day time.
But in the open air it will mix with 'normal' air and thus the reading will not be as high as in your sealed room.
First reason is that there is so much O2 in the air.
Let's say your room is 2 meter x 2 meter x 2 meter. That is 8000 liters of air, of which about 20% is O2. That is 1600 liter of oxygen in gaseous state. So that is 1.6 M3. It will weigh 1,6 x 1.4 kilo = 2.24 kilo of O2.
No way that plants that can fit in such a room will absorb this amount of O2 in one night.
Second reason is that a room is never completely sealed. And O2 will slip through the tiniest hole.
The article of medteknutrients is nice, but there is also some pseudo-science in it.
Higher CO2 levels are not dangerous to plants (CO2 poisoning is bro science. Yes, it can happen, but then you need extremely high values. Same with people)
Perhaps you still know this 'fact' from the past that one should not have plants in the bedroom, because it would consume all the oxygen.
It was total nonsense. An average house plant (not cannabis) would absorb about 50 ml of oxygen per night. Even if you have a small bedroom of about 2 x 3 x 2.5 meter = 15 M3. 3 M3 of that is oxygen. That is 3000 liter = 3,000,000 ml of O2.
@SourDeezz Your CO2 ppm is so high because your CO2 will stay mainly in the room. The plants produce CO2 in the night.
If you take your CO2 controller and go in a forest at night, you will also measure a higher amount of CO2 as during day time.
But in the open air it will mix with 'normal' air and thus the reading will not be as high as in your sealed room.
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