Could anyone help with a ventilation question???

Hi,
Just wondering if anyone can help me with this as i'm not really sure how to do the calculations.

I've got a small triangle room with a 400w HPS inside. The temps have been staying low but now the weather has warmed up, so has my room.

I've already got a 4" extractor fan taking air out through a carbon filter which extracts 22 litres per second.

Basically my question is this. I've now brought another inline fan to take air in and this says it moves 130 m3 per hour.

so....... if the intake fan is pushing in more air than the extractor fan can take out, will this cause me problems??

Am i right in thinking that the extractor is taking out air faster than the inline is putting it in??

I'm not the best with my maths

Any help would be great!!!

set them both up to suck out.....

You want to try to take out more than you're putting in. This will give you negative pressure in your grow which keeps odors from getting out as well as aids in velocity.

but you'll have to make or buy another filter.....

Ok cool. Thanks

So should i not bother having a fan taking air in and just cut some vent holes and let the 2 extractor fans pull the air in by themselves??
But then i'm gonna have problems with light leaks out of these vent holes aren't i????

Yea I would think that you could have an issue with light leaks, unless you have your lights set up to be on during the day time, and turn off at night and there are no other lights that are on anywhere near the tent. If you want to cut another intake hole, is it in drywall, a tent, etc. you could use one of those dryer vent hoses and stick about a foot out the hole and use duct tape to seal up any gaps, and then connect the other end of the hose to the fan. I wouldn't bother with having two extractor fans. How hot does it get in the room? I would have the extractor fan pull more air out than what is being pulled in. Also you could set up another small fan in the room blowing over the tops of your plants. With the air being blown over the tops of the plants it will help get rid of some of the heat that just lingers around the plant. Get one of those oscilating (sp?) fans for your room and have it run 30 minutes before the lights turn and up until 1 hour after the lights turn off.

to my understanding... and correct me if I'm wrong... optimal temperatures for weed are between 27-30 degrees C (80-86 degrees F)...

taipanspunk said:

to my understanding... and correct me if I'm wrong... optimal temperatures for weed are between 27-30 degrees C (80-86 degrees F)...

Click to expand...

i run my flowering room at 24C and my clone/mother room at 26C


I keep my canopy temps below 28C . Higher temps are used with Co2 systems.


About ventilation.
You should work out the volume of your area.


22 litres per second fan is a 80m3h fan.


A 400w light is capable of having a 1mX1mX2m growing area. This means you should have a minimum of a 120m3h fan for air exchange and some cooling ability.

You could use a powered intake but if it were me i would upgrade your exhaust fan to a 5inch Vortex with around 250m3h or 69 litres per second.

Its easier to remove warm air than it is to intake cold.


Really reading is all you need to do on the subject. STOP CHEAPING OUT on extraction.



J

Thanks a lot for all your info.

The room is a triangle shaped one in the corner of a room. I can't really work it out. I know u do WxDxH. Do you just work it out as a square and half it???? Anyway, the three sides are 1m x 1m x 1.4m and its 1.5m high. so its a kind off small room.

I managed to cut another hole in today and its now brought the temp down to about 84f which i know is pretty good and cured any light leak problems.

Whilst i'm here though, bearing in mind the rooms quite small and restricted with height, how long do you think i should veg for?? There's 2 widow plants in there and there on about day 15 from seed. But they are comin on great but are stayin really low and bushy. does that sound alright??