Need some experienced help no idea what to do!

Hi guys,

So my problem is in my 80cm x 80cm x 180xm tent my temperature will not go below 90F.

I am using a small extractor fan attached to a small carbon filter the fan is 105m3/h (61cfm), they say that a carbon filter + some bending in the duct reduces the airflow by like 20% so I guess its even lower.

I have 2 passive intakes (A length of duct and a open vent at the bottom).

I am using a MarsHydro 600w LED light (275 true watt).

My temperature outside the tent is around 70F to 75F.

I also have a 6inch fan inside to move air around but when I put this fan on it actually INCREASES the temperature inside the tent!

My question to you guys is if I upgrade my exhaust fan upto 180m3/h (105cfm) will this be enough to bring my temps down or will I have to downgrade my light aswell to a 300w LED?

All help is appreciated, im so unsure whether to return just the extraction kit, just the light or both?!

Thanks in advance!

Can't dial down that light? then I'd jump to a smaller light, but first I'd be getting a larger grow tent, at least 1200x1200 (4'x'4')
...as you really NEED to make this venture worth your time and effort ....good luck

vostok said:

Can't dial down that light? then I'd jump to a smaller light, but first I'd be getting a larger grow tent, at least 1200x1200 (4'x'4')
...as you really NEED to make this venture worth your time and effort ....good luck

Click to expand...

The light is just a plug and play and the tent im using is the biggest i can have in my space unfortunately. Do you think I need to downgrade my light then aswell as upgrading my exhaust fan? Thanks

All your gear is good for the job, it just the temps thats wack? a larger grow tent gives you more air and space, a bigger extract fan will move more hot air, a smaller light, will delay harvest, even growing Sativa's at 90F, is possible, or the obvious.............. and avoid growing this time of year, due to heat is an option, in my zone I do the same but with mold

Your extractor fan is not adequate. Get a 180 CFM setup with a fan speed controller. You don't want to downgrade the light. That's barely enough watts to fill a 3x3, in my opinion.

Also, vent your exhaust into another room. If the tent is in a bedroom then get a drill with a 4" hole saw and cut a hole in a wall to run your hose through. Anywhere you can vent the air to is fine. Out a window, into a bathroom, into an attic etc..

Also, if you can use a piece of hose for the intake at the bottom of the tent, but pull air from a nearby window..
Run lights at cool times of day or night. I run mine from 10pm to 10am.

I have a 400w HID and with an air cooled hood, and 180 cfm fan and 3x3 tent I can keep my temps 2 degrees above ambient using the adjustments suggested above.

Yes, a fan inside the tent will raise temps in some cases.. try blowing the fan from the floor towards the top of the tent.

All in all, you simply need to extract more air at faster rate and deposit that air somewhere else.

vostok said:

All your gear is good for the job, it just the temps thats wack? a larger grow tent gives you more air and space, a bigger extract fan will move more hot air, a smaller light, will delay harvest, even growing Sativa's at 90F, is possible, or the obvious.............. and avoid growing this time of year, due to heat is an option, in my zone I do the same but with mold

Click to expand...

walmart has 240cfm 6inch duct fans for 28 dollars

daloudpack said:

walmart has 240cfm 6inch duct fans for 28 dollars

Click to expand...

i dont know why i said walmart i meant lowes

sunny747 said:

Your extractor fan is not adequate. Get a 180 CFM setup with a fan speed controller. You don't want to downgrade the light. That's barely enough watts to fill a 3x3, in my opinion.

Also, vent your exhaust into another room. If the tent is in a bedroom then get a drill with a 4" hole saw and cut a hole in a wall to run your hose through. Anywhere you can vent the air to is fine. Out a window, into a bathroom, into an attic etc..

Also, if you can use a piece of hose for the intake at the bottom of the tent, but pull air from a nearby window..
Run lights at cool times of day or night. I run mine from 10pm to 10am.

I have a 400w HID and with an air cooled hood, and 180 cfm fan and 3x3 tent I can keep my temps 2 degrees above ambient using the adjustments suggested above.

Yes, a fan inside the tent will raise temps in some cases.. try blowing the fan from the floor towards the top of the tent.
All in all, you simply need to extract more air at faster rate and deposit that air somewhere else.

Click to expand...

This is is some really valuble information sunny, sounds like you know what your doing and your confirming exactly what i was thinking.

I just dont want to upgrade my exhaust and then to find im still having problems because the light is over heating the room, then I wont be able to return it.

I have no plants in there right now im just running constant tests to make sure its suitable for growth which atm I think its not.

My plan was to make a hole in the ceiling and vent my duct through there while drawing air in from the window, exactly like what you said.

Sunny, do you know how much your light increases your temp without any extraction on? Im about to go test that now and see how much my temps get up to with no exhaust on, then put on my exhaust and see how many degrees it reduces the temperature by. Ill keep you updated

Thanks for your words man really appreciate it

Well, what I would do is leave the flap open. Herb does not really smell that strong until the 2 or 3 week of bloom, and even then not really bad,( some strains do smell stronger than average) as long as you don't go moving them around, some ONA gel will mask whatever is left. Cutting/trimming is when you really have to watch out for odor. You will never get the temps down to 85 ( above that temp starts to affect growth.) in that setup, unless the outside air is around 70, and you are really pulling some air through.
If you are doing 1 plant, which is really all the room you have for, a downsize in lighting to say 300w is all you really need, for excellent results. Sell your existing light to a fellow stoner, or save it for later, because you definitely will want to grow bigger and more in the future. That is a guarantee. Good luck

sunny747 said:

Your extractor fan is not adequate. Get a 180 CFM setup with a fan speed controller. You don't want to downgrade the light. That's barely enough watts to fill a 3x3, in my opinion.

Also, vent your exhaust into another room. If the tent is in a bedroom then get a drill with a 4" hole saw and cut a hole in a wall to run your hose through. Anywhere you can vent the air to is fine. Out a window, into a bathroom, into an attic etc..

Also, if you can use a piece of hose for the intake at the bottom of the tent, but pull air from a nearby window..
Run lights at cool times of day or night. I run mine from 10pm to 10am.

I have a 400w HID and with an air cooled hood, and 180 cfm fan and 3x3 tent I can keep my temps 2 degrees above ambient using the adjustments suggested above.

Yes, a fan inside the tent will raise temps in some cases.. try blowing the fan from the floor towards the top of the tent.
All in all, you simply need to extract more air at faster rate and deposit that air somewhere else.

Click to expand...

Ditto what he said.

daloudpack said:

walmart has 240cfm 6inch duct fans for 28 dollars

Click to expand...

Im living in the UK

nk14zp said:

Ditto what he said.

Click to expand...

Thanks for your input nk14zp, im running a test right now. Putting the light on with no extraction for an hour. Seeing what the temps are then putting on the extraction and see how much it bring the temp down by ill have some pictures to upload and show you guys

Hey guys just had my light on with no extraction for about 1 hour 30 mins now and these are the results seems to of increased the temps of my small tent by about 10C or 50F.

Is that normal?

Just flicked on my extractor fan and going to check in about 30 mins or so how much it takes down my temperature by. (How much heat its actually removing)

Also, the temperatures that are shown on my hygrometer are fairly different but the temperature rod and the actual unit are right next to eachother. Any have any ideas about this? Bad hygrometer or some explanation?

Whereabouts in the tent is the hygrometer? Is the light shining on it?

Roobarb said:

Whereabouts in the tent is the hygrometer? Is the light shining on it?

Click to expand...

Yes its sitting ontop of a book, ontop of my pot i am going to use about 35 inches away from the light

Is it possible that it's absorbing the radiant heat? I put mine in the space over the light but not in contact with the hood.

Roobarb said:

Is it possible that it's absorbing the radiant heat? I put mine in the space over the light but not in contact with the hood.

Click to expand...

Could be im not sure how that works though

If it's sitting on the warm surface of the hood or in the direct light it won't give a correct reading of your air temp because the device itself will be absorbing heat

You've made a bunch of threads all with the same stuff posted.

Either ditch the tent and grow in an open area or like others have told you, go with a bigger tent

Also some hygrometers/thermometers are + or- 5 degrees or so.