Tent heat

Hi all, I'm on my last week of veg in a 1.2x1.2x2.0 tent running a 250w MH temperature is at a nice 25°c 26°c light on and about 17°c 18°c lights off.

For flower I have a digital ballast where I can turn down my 600w HPS bulb for heat reasons, but I'd say this will affect lumens and not give my plants what they need. Also just bought a dehumidifier to keep RH down.

My question is what's the best way to keep my temperature down keeping my HPS at 600w?

Make sure your measuring temp correctly by not having thermometers in direct light.

But the best way to keep heat down is to exchange more air, extract more. But it has to be vented outside.

coreywebster said:

Make sure your measuring temp correctly by not having thermometers in direct light.

But the best way to keep heat down is to exchange more air, extract more. But it has to be vented outside.

Click to expand...

That's what I'm doing. Inlet from under the floor and venting old air outside 5" rhino pro carbon. Was thinking about plastic bottles filled with water then frozen in front of a fan, would that reduce temp?

Trichrome_kush said:

That's what I'm doing. Inlet from under the floor and venting old air outside 5" rhino pro carbon. Was thinking about plastic bottles filled with water then frozen in front of a fan, would that reduce temp?

Click to expand...

I would have to see your set up to know if there is anything wrong.
But it does greatly depend on what the air temp coming in is. Obviously that's your starting point so if its a hot country your in then you are already at a disadvantage.
So your using a 5" fan too? What brand?
Air cooled hoods will remover 30% of the heat too so its an option if its needed.

You can try plastic bottles frozen but I don't think it will make much difference as the air doesn't have enough contact time with the cold to lower the temp.

coreywebster said:

I would have to see your set up to know if there is anything wrong.
But it does greatly depend on what the air temp coming in is. Obviously that's your starting point so if its a hot country your in then you are already at a disadvantage.
So your using a 5" fan too? What brand?
Air cooled hoods will remover 30% of the heat too so its an option if its needed.

You can try plastic bottles frozen but I don't think it will make much difference as the air doesn't have enough contact time with the cold to lower the temp.

Click to expand...

I'll post a picture later when I'm home

Here's pictures as requested

Trichrome_kush said:

Here's pictures as requested

Click to expand...

If possible get that intake lower down.
Raise the thermometer just above the light line but not above the lamp itself.
Nice and clean in there. I cant see the fan properly but the little I can see looks like a legit extractor.
You say the heat goes right out of the room? Out of a window or elsewhere?

Here is a good chart which shows the airflow needed to remain x degrees above ambient air with y wattage

get the light closer,looks a fair bit away.

Trichrome_kush said:

Here's pictures as requested

Click to expand...

You have no hope of really cooling that tent down without a sealed light housing.

He needs a air cooled hood. Is all I ever use in tents.
Like this one, I use digital ballasts.

coreywebster said:

If possible get that intake lower down.
Raise the thermometer just above the light line but not above the lamp itself.
Nice and clean in there. I cant see the fan properly but the little I can see looks like a legit extractor.
You say the heat goes right out of the room? Out of a window or elsewhere?

Here is a good chart which shows the airflow needed to remain x degrees above ambient air with y wattage

Click to expand...

Thanks very much for your nice reply. I have a 5" extractor with a 5" rhino pro carbon filter. The white appliance is a dehumidifier which I'm keeping RH at 55% just now for veg. Was thinking of fitting a 5" electric duct fan to my intake for more cool air in. Intake is from under floorboards and out take us directly out the window.

Mr Blamo said:

He needs a air cooled hood. Is all I ever use in tents.
Like this one, I use digital ballasts.

Code:

https://www.amazon.ca/Sunstream-inch-Reflector-Light-System/dp/B07FJM7ND3/ref=sr_1_1_sspa?ie=UTF8&qid=1536684205&sr=8-1-spons&keywords=6+inch+light+reflector&psc=1

Click to expand...

Cheers man. Looks a good unit. Will look into that.

Trichrome_kush said:

Thanks very much for your nice reply. I have a 5" extractor with a 5" rhino pro carbon filter. The white appliance is a dehumidifier which I'm keeping RH at 55% just now for veg. Was thinking of fitting a 5" electric duct fan to my intake for more cool air in. Intake is from under floorboards and out take us directly out the window.

Click to expand...

In veg don't you want higher humidity?

Trichrome_kush said:

Cheers man. Looks a good unit. Will look into that.

Click to expand...

The intake and outtake is 6 inch.
I read your using 5 inch...just letting you know you will need a couple elbow duct pieces that go from 5 inch at one end and 6 inch on the other end to connect to the hood if you decide to get it.

i grow in a tent with 2 x 600w hps. i use a 10inch duct fan with fan controller to keep temps just so.. more air extraction is all that is needed to keep things cooler but try and extract the air out of the building to prevent heat build up.

i dont use cool tubes or cooled huds either just big fans for keeping the air temp uniform throughout the tent and good extraction.. very rarely go over 28deg C with both light on..

also dimming a 600w to a lower power will also shorted bulb life or so i hear lol.

Happy Growing

Well I done a heat test last night with my 600w HPS and my dehumidifier was flickering between 26.5°c and 27°c so can't complain. Think that's a good temperature for them

In fact I just left the flowering bulb in and switched to 12/12

Is canna boost really worth all that expense, or is it just a gimmick?

Blalack55 said:

In veg don't you want higher humidity?

Click to expand...

Went into flower last night and have controlled my RH to 45% and will drop again to 40% week 5 then 30% weeks 6 and 7

TacoMac said:

You have no hope of really cooling that tent down without a sealed light housing.

Click to expand...

Done the temperature test last night temp was 26.5°c to 27°c

Trichrome_kush said:

Went into flower last night and have controlled my RH to 45% and will drop again to 40% week 5 then 30% weeks 6 and 7

Click to expand...

Oh ok cool, honestly I was asking because I'm on my first grow and I've read a lot but it seems like there's a lot of different opinions on this lol

Trichrome_kush said:

Well I done a heat test last night with my 600w HPS and my dehumidifier was flickering between 26.5°c and 27°c so can't complain. Think that's a good temperature for them

In fact I just left the flowering bulb in and switched to 12/12

Is canna boost really worth all that expense, or is it just a gimmick?

Click to expand...

Boost is the only thing I don't have but there's a lot of reviews on canna boost some swear by it others say not worth it but if I could get it I probably would, and you can YouTube videos on hood temps and people put like q thermal wrap or something like that and it really helps with temperature because it absorbs the heat but that's a little bit of what I could find