Ok I have a 1m by 1m by 2m budbox with a 250 watt hps a 4 inch extraction fan and carbon filter fitted at the top. I cant get the temps below 92f. Im thinking about air cooling the light but this would mean taking off the carbon filter. Can the carbon filter be connected outside the tent on the exhaust so that the air is blowing through it rather than being sucked through it? thanks.

welcome smokeyjoe2
I'd say yes, but look into where your intake air is coming from. hopefully a different area to where you're exhausting to.

im sure your not meant to blow through a filter you could rig it up like so


filte-cooltube-fan all inside the tent though

Hello the intake is just 2 vents in the bottom of the tent and im exhausting in the same room.

cheers not sure what a cooltube is ill take a look.

it looks like thats the source of your heat issue
and i'm certain you can blow or suck through a C/F.
cooltube=££££'s
changing intake=£ !
E2a : is it possible to get fresh air from a different area with a length/s of ducting connected to your intake/s

Yes but would I then need an intake fan as well? would the fan be powerful enough?

where are you measuring the temps ?

Helli Im measuring the temps right at the plant level theyre only about 6 inches at the mo.

'tis known as the passive/active debate
i'd have a mooch around the boards
do a search for passive or Click here!
and as compostverte asked , as i forgot.

so the thermometer is under the foliage ?

How high is the light ?

I'm using two of those lamps in a significantly smaller space - but it has oodles of "passive ventilation".

Also bringing in air from the same room your venting i.e no fresh air is gonna be fairly pointless for one you wont get your tempos down as all your doing is re-circulating the air and for 2 there will be sod all co2 after your plants have used it up when they need more and more.

You really need an air intake.

The light at the moment is near the top but raising it doesnt seem to have made much difference to the temp. The thermometer is sitting on the compost right next to a plant theres no foliage covering it.

Ok cheers. I have an air vent in the room if I connect to it with ducting do you think the one fan will have enough power to pull the air up through the tent and through the ducting that connects to the outside vent?

Ive looked at the threads on the subject Im just hoping to get away without another fan.

Depends on the fan your using to be fair and the length of ducting btwn the fan to the tent.

With a 100 dia fan with a CF attached, there is no chance of inceasing intake air. You will need a second 100 dia fan at least, to pull air from the wall vent, through your box.

As pointed out, with intake and extract taken from the same space, you will simply recycle depleted AND already heated up air.