How many BTU can be COOLED \w EXHAUST before AC is needed

Renfro said:

Just FYI, the HPS will put out more than 3.4 BTU/hr. The math on a 1kW HPS is around 4500 - 5000 BTU/hr and a DE HPS is usually mathed at 6000 BTU/hr for building design purposes. I have rooms with 10kW of HPS lights, some DE and SE... Those rooms have 4 ton AC units that are pushed to the limits. So I suspect the HPS number is somewhere around 4.8 BTU/hr per watt.

My math says that your tent needs around 1200 CFM to keep it's temps within 3 degrees of the ambient. Thing is, the ambient may just keep rising as the tent warms up the basement.

Only way to find out if your setup will stay cool is to fire it up without plants for 24 hours and see if it holds temp. It takes that long because stuff will gradually heat up. A test fire is always smart on a new grow.

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Carolina Dream'n said:

Testing a room with no plants in it is pointless. They plants are going to change your temp and humidity, by transpiration.

Step into a greenhouse in the middle of summer with no plants. It’s hot as shit. Step into a greenhouse full of plants in the summer, it’s already 10 degrees cooler than previous greenhouse because of water in the air. Same concept.

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JungleSlut said:

Yeah I gotta do something. I'm only running that 600watt ballast on 75% so around 400 watts right now not even full power and dont even have the HPS in there yet.
View attachment 4377526

Even this one ive only been running those 6 cobs, havent even turned on the other 300 watts of blurple yet so I definately will run into some heat issue when everything full power.

I'm gonna swap out that 600 watt hid for another light

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Armyofsprout said:

It’s not pointless as it gives you a max reference point. If you run your lights with nothing and the temps are ok then you know you’ll be fine with the plants in there.

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Armyofsprout said:

like I said man simplify it. I wouldn’t go mixing all these different lighting types because you’re probably just gonna end HK switching time all LED later on anyways. I would just use the 2 led you have now and maybe grow on like half side of the tent. Or sell that HID and just go LED like your other two but I wouldn’t mix CMH in there because you’re gonna make it more difficult for yourself having to buy different bulbs and components etc.

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JungleSlut said:

FIRST
I have a wireless temp\hydrometer it
-It reads 29c inside the tent and 21c ambient room temp
temp
- I Have an ink bird humidty AND temperature environmental controller. My exhaust fans are hooked up to the temperature plug-in not the humidity one
-i have the fans set to kick in when temperature hits 23.5c
-when my wireless.temperature gauge reads 29c
The inkbird probe reads around 25c (big fucking difference, I cleaned.the probe and everything, and still reads 4 degrees celcius lower than the other one. So I'll have to get something else to test the temp and see wtf is going on
So maybe the temp in my room ain't as bad as I think

SECOND
When I water my plants they were getting 1 litre of water each
The fans would kick off at night because of the environmental controller. The humidity history of my reader would read up to 90% RH sometimes especially with all The rain we had been getting.

I'll definitely get a dehumidifier because when I have more plant mass in there perspiring and more water in the soil evaporating into the atmosphere its gonna raise the humidity in that tent. And I did not fight tooth and nail to keep these plants alive just to run into bud rot down the road.



I've got 4 plants under a scrog branches already weaving in and out man
I just got rid of 3 cobs light bars because they stressed my plants from the direct beam of light and I didnt have any hanging height instruction with them and they didnt state what angle of lens they were, 45 degree, 90 degree, 120 degree I had no idea. And the manufacture kept ignoring me when I asked for over two months by email.
So the cobs being too close to my plants stressed them, they stopped drinking and got overwaterd. So i sent the cobs back, got the CMH and the QB

-ACCEPT for the plant under the metal halide kept on going without skipping a beat. It's why I bought that CMH in the first place, less heat, less power, better spectrum. I Liked the way the plant handled itself under that hid.
3plants under those leds and they shit the bed
1 plant under MH and he kept kicking ass
I learned something valuable there.

I'm not scratching my head calling for an bailout I'm just trying to see what my options are with the AC and exhaust thing so I have a plan in place before i need that plan you feel me.
IM jUST TRYING to plan ahead.

Still got a bit of screen to fill out so I got some time before flip. Plants are starting to recover slowly because I been babying them.
Still got a bit to go.

This was an experimental grow. I maybe didnt plan to go this big and all over the place but once started I decided thats exactly what it was gonna be. I was gonna make all the mistakes I could, try everything, fim, top, lst, get as much experience I could in one grow and get it out the way.

Fimed my plants too young and they took a long time to recover as roots hadnt developed yet.
Learned something

Overwatered seedlings
Learned something

Lights too close
Learned something

Plants weren't drinking cus were stressed
Learned something

You say u need experience first to grow and equipment second.
I appreciate you looking out but I look at it from a different perspective.

If I would of had a par meter and a soil tester to test the soil and how wet it was I wouldnt have overwatered my plants they would of kept growing like they were, and doing good and we wouldnt be having this conversation. OR AT THE VERY LEAST a recomended hanging distance from light to canopy

My plants still alive bro and I'm learning how to roll with the punches now.
It's not all bad they looked like this in veg tent

Before they went into big tent
View attachment 4377624

THIS IS ONLY 5 DAYS AFTER
under those bloody cobs
View attachment 4377621
View attachment 4377620

ACCEPT FOR THIS GUY
UNDER THE METAL HALIDE
View attachment 4377622

You see difference. This is why I'm gonna run two CMH (hid lights across from two Quantum boards) I liked the way HID handle business. I like the radiant heat. Just gonna tone it down with CMH and leave hps put of the equation because of the excessive heat.


It's been good. You guys have helped me out alot with my future decisions and I really appreciate it

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Armyofsprout said:

Aw man bummer to hear about the lighting and plant issues. You learned a lot in this process though and that’s what I meant. Gaining that knowledge from things going bad is kinda the best way to go. Now you have a general idea of what you need and the direction to go in.

Do you have the QB hooked up? Hows that working out? I think you inspired me to get the 100W QB and run both lights in my 2x4 if they can fit

but I agree yeah get that HPS out the way and heat in check first and foremost.

i also have the sensor from my light and my probe from my fan environmental controller reading temp differences of 3-5 degrees as well and I agree it’s annoying. I think maybe the probes are just different quality.

glad you have a plan. It’ll all work out. Are your plants super stressed right now? If they are Can you put them outside in sunlight unti you get your situation situated?

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Armyofsprout said:

haha. Trust me man ive been there done that with the overdoing it phase and I’m younger than you so I get it. But theres only sooo good you can get with your grow at first. What makes your bud amazing with high yield simply comes from the experience first and equipment second.

but yeah you don’t need a humidifier from the sounds of it. You may not even need an AC. I would just sell that light and get another solid LED. It doesn’t have to be a quantum or anything crazy. Just get something like I got off amazon maybe. Those are solid lights and I’m sure you already know to go by the true wall wattage and not the title wattage lol. Mine says 2000w but is 380W wall draw. I didn’t want to overheat my tent. But after this grow I’ll probably swap if for the 3000w/615 actual draw

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JungleSlut said:

FIRST
I have a wireless temp\hydrometer it
-It reads 29c inside the tent and 21c ambient room temp
temp
- I Have an ink bird humidty AND temperature environmental controller. My exhaust fans are hooked up to the temperature plug-in not the humidity one
-i have the fans set to kick in when temperature hits 23.5c
-when my wireless.temperature gauge reads 29c
The inkbird probe reads around 25c (big fucking difference, I cleaned.the probe and everything, and still reads 4 degrees celcius lower than the other one. So I'll have to get something else to test the temp and see wtf is going on
So maybe the temp in my room ain't as bad as I think

SECOND
When I water my plants they were getting 1 litre of water each
The fans would kick off at night because of the environmental controller. The humidity history of my reader would read up to 90% RH sometimes especially with all The rain we had been getting.

I'll definitely get a dehumidifier because when I have more plant mass in there perspiring and more water in the soil evaporating into the atmosphere its gonna raise the humidity in that tent. And I did not fight tooth and nail to keep these plants alive just to run into bud rot down the road.



I've got 4 plants under a scrog branches already weaving in and out man
I just got rid of 3 cobs light bars because they stressed my plants from the direct beam of light and I didnt have any hanging height instruction with them and they didnt state what angle of lens they were, 45 degree, 90 degree, 120 degree I had no idea. And the manufacture kept ignoring me when I asked for over two months by email.
So the cobs being too close to my plants stressed them, they stopped drinking and got overwaterd. So i sent the cobs back, got the CMH and the QB

-ACCEPT for the plant under the metal halide kept on going without skipping a beat. It's why I bought that CMH in the first place, less heat, less power, better spectrum. I Liked the way the plant handled itself under that hid.
3plants under those leds and they shit the bed
1 plant under MH and he kept kicking ass
I learned something valuable there.

I'm not scratching my head calling for an bailout I'm just trying to see what my options are with the AC and exhaust thing so I have a plan in place before i need that plan you feel me.
IM jUST TRYING to plan ahead.

Still got a bit of screen to fill out so I got some time before flip. Plants are starting to recover slowly because I been babying them.
Still got a bit to go.

This was an experimental grow. I maybe didnt plan to go this big and all over the place but once started I decided thats exactly what it was gonna be. I was gonna make all the mistakes I could, try everything, fim, top, lst, get as much experience I could in one grow and get it out the way.

Fimed my plants too young and they took a long time to recover as roots hadnt developed yet.
Learned something

Overwatered seedlings
Learned something

Lights too close
Learned something

Plants weren't drinking cus were stressed
Learned something

You say u need experience first to grow and equipment second.
I appreciate you looking out but I look at it from a different perspective.

If I would of had a par meter and a soil tester to test the soil and how wet it was I wouldnt have overwatered my plants they would of kept growing like they were, and doing good and we wouldnt be having this conversation. OR AT THE VERY LEAST a recomended hanging distance from light to canopy

My plants still alive bro and I'm learning how to roll with the punches now.
It's not all bad they looked like this in veg tent

Before they went into big tent
View attachment 4377624

THIS IS ONLY 5 DAYS AFTER
under those bloody cobs
View attachment 4377621
View attachment 4377620

ACCEPT FOR THIS GUY
UNDER THE METAL HALIDE
View attachment 4377622

You see difference. This is why I'm gonna run two CMH (hid lights across from two Quantum boards) I liked the way HID handle business. I like the radiant heat. Just gonna tone it down with CMH and leave hps put of the equation because of the excessive heat.


It's been good. You guys have helped me out alot with my future decisions and I really appreciate it

Click to expand...

ChiefRunningPhist said:

FYI
The blurple might be pretty close to 1.9 or 2.0μmol/J. This means you won't cut any heat by swapping a 2.0μmol/J HID for a 2.0μmol/J blurple.



Nice.

CMH, can't get a much better SPD than that. At 2.0μmol/J, but includes WV all the way to UVB.. I'd add some red strips in bloom or just let her do her thing. Red will help make more buds while the enhanced CMH SPD will add to the quality that you only get with a wide SPD like that. Going to hypothesize that a big reason the MH pulled through was due to it's SPD.

I run my fans 24/7, especially right after lights off, that's the time when you'll get the biggest RH spike, cause air temp drops, and in turn the air becomes denser, and in turn the water being suspended in the air condenses and drops out as dew or condensation.

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