Extraction, heat issues !

Hi, not new to this game but just want to confirm, I run 4 x600w hps in a 2.2m square and 2.4 high and have a can fan 250mms 10" running 830m3/h reduced by filter to say 730 and temps are about 32c 34c tops daytime and down to 29c 28c at night ! Need to bring that down 5c 6c night time so what's I need ??? Filter does 1600m3h so ...... Intake is passive !

So your running 4 600w lights in a roughly 7ft by 7.5 ft area? And you have heat issues go figure lol that’s way to much light for that amount of space you only 2 of those 600w lights in that amount of space

Yeah you need ventilated hoods, with 8" all the way at a minimum.

Seriously ? Your telling me with a serious face that 2x600w will do over 2mx2m ? No gentlemen it won't ! 2x600 doesn't leave a big enough foot print !
either way, I should have stated a bit more, going into bloom Friday and through the night for temp reasons ! sorted I think for now, to sort out I raised the lights a few inch added another circulating fan aiming slightly up which takes some heat from the leaves and lowers air temp just enough ! Through the night I'm around 26c which is doable !! I am going to get a slightly larger extract fan anyway, go from 800m3h to 1000/1100m3h just to help out some more !!

In your first post you said 2.2 square meters which could be 1 x 2.2,, and now you say 2 x 2 meters which is 4 square meters, you confused us.

Nixs said:

In your first post you said 2.2 square meters which could be 1 x 2.2,, and now you say 2 x 2 meters which is 4 square meters, you confused us.

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I apologise, it's closer to 2.2m square but with extra height where filter, fan and silencer are situated. Under the extraction is 2m high so lights go 2m high !

Here are some pics !! It's not so bad now heat wise but it will creep up over time even through the night !! Daytime, right now is between 26 and 30c but tomorrow will only be nights !

What is the temp of the air that you are sucking in? Quick way to reduce temps is to run a portable AC next to the tent and have it blow cold air directly into your tents intake.

Your sweet spot day time temp is 23.5 - 25.5. You will actually harvest more with 2 X 600 lights running at 25 degrees leaf temp than you will with 4 X 600 at 32-34 degrees. Day time temps that high will seriously damage your yields

Those plants look stressed, can you cool the source of fresh air? 30 plus is pretty warm under hps, a few degrees makes a difference. Running straight smooth galvanized ducting will help extract more air with the current fan. Forcing air in over passive won’t really help a lot for the effort it could take if the source air isn’t much cooler, could make it smell too if you get into pos pressure.

Do you have any budget for cooling? It would be cheaper to grab a window shaker or portable then adding fans and any amount of cooled hoods. I run open wings too and have used vented hoods. I like bare back. Either way, you need to exchange the air faster or cool the air source ASAP.

The bigger plants, older infact were all bunched up which never helped, tomorrow will only be nights so temp will be right for a another month.
Temp of the air going in depends on the time of day/night ! I have a large fan pushing air into the room the tent is in which helps more than one would think !

I'm surprised no one has asked if I'm running digital dimmable ballasts ! I am and when the problem arises I will turn them down too ! Environment is everything and heat is a killer of a good crop !

what are your target temperatures?

Target is 25c lights on 26 c at worse really. I'd like perfection but perfection is expensive and I've had to buy everything again !

Yeah the plants at the edges are definitely stressed out a bit, they were all at the back together with high temps ! I moved plants around to help with air circulation.
My issue has really been 18hours lights on with 7 hours in warm days ! The temps go right up until Sun dips but tomorrrow it's only night time temps to think on which isn't so bad. I think I will still use a bigger m3h extraction fan. I used to run 700m3h on a 1.2x2.4m tent with 2x600w hps due to same problem. I do not like air cooled hoods either ! I've been thinking a cheap ac but cheap equals moisture and I can't afford expensive ac which would be suitable, when funds are available.............

A.c. reduces moisture.

Original StinkyG said:

Yeah the plants at the edges are definitely stressed out a bit, they were all at the back together with high temps ! I moved plants around to help with air circulation.
My issue has really been 18hours lights on with 7 hours in warm days ! The temps go right up until Sun dips but tomorrrow it's only night time temps to think on which isn't so bad. I think I will still use a bigger m3h extraction fan. I used to run 700m3h on a 1.2x2.4m tent with 2x600w hps due to same problem. I do not like air cooled hoods either ! I've been thinking a cheap ac but cheap equals moisture and I can't afford expensive ac which would be suitable, when funds are available.............

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A few questions for you.

what is the weather like where you are? Approx temps?

where is your exhaust fan dumping all of its air?

Original StinkyG said:

Seriously ? Your telling me with a serious face that 2x600w will do over 2mx2m ? No gentlemen it won't ! 2x600 doesn't leave a big enough foot print !
either way, I should have stated a bit more, going into bloom Friday and through the night for temp reasons ! sorted I think for now, to sort out I raised the lights a few inch added another circulating fan aiming slightly up which takes some heat from the leaves and lowers air temp just enough ! Through the night I'm around 26c which is doable !! I am going to get a slightly larger extract fan anyway, go from 800m3h to 1000/1100m3h just to help out some more !!

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Uh... i run 2 480w in a 5x10 no problem if anythings its too much light. Invest in an AC only way ur getting those temps down

All extracted air goes outside, night time temps is where I'm at, I'm checking, outside is 6c inside not sure without checking. Now I'm only growing through the night I should be fine, gonna grab a new extraction fan anyway as I can get a hyper v2 for cheap 10" so should keep me to fine till end of this grow n have more funds. However as soon as I'm done I was want to change my grow to led and hps or led and cmh and as temps will sore middle June day and night I want to run ac and maybe co2 , maybe ? My space is c hanging too, space will be about 8' x 8' , maybe 9 foot square and 8 foot high and running probabl y 2x 660w led bar lights and 4 x 250w hps or led and cmh not sure of amount either 2 or 4 ?? All pumps , ballasts etc will be outside of space, How much a.c would I need ?

2x 480w of what ?

Only if it's good ac which I cannot afford till this grow is complete ! Cheap ac is evaporative, that is what I meant. If i could afford a good ac split unit I would have one ! Sorry for not being clear.