4x4x7 tent...ventilation help!

[thewhitelotus]

Just got my 4x4x7 Earth Worth tent setup and I had a couple questions in regards to ventilation. The tent has 3 6" duct vents, 2 4" duct vents, and 3 3x19" passive intake rectangles located at the bottom of the tent on 3 sides

Im currently running a 400w super sun 2 HPS that is NOT aircooled. Ambient temps in the room which the tent is located is around 70-75 degrees. Here is a list of the equipment I have....

- Stanley blower modded to attach to can 33 filter
- Hydrofarm 100cfm Active Air Blower
- (2) 135cfm 5" square fan
- 2 osc. fans

what setup of said equipment would you suggest for keeping temps down in the tent? Id prefer to use passive intake for negative pressure but this is all new to me so im not sure

thanks!

 

[facedark]

have a fan blowing air onto your hps bulb, honeywell fans are very good for this purpose because how they push the air into a beam sort of.

 

[RonSmooth]

First, I would fire up the light to see how how it gets. Once it gets past 90, shut it off and try this configuration:

Hang the filter/blower at the top of the tent so that it sucks hot air through the filter and exhausts it out.

Leave one of the intake vents at the bottom open.

Close all the other openings.

Then close it up and fire up the light again. See where the temps stabilize. If it is still hot, you'll need a stronger exhaust fan or an air cooled hood.

A single oscillating fan will be plenty for air movement within the tent.

 

[xfredo1990x]

yup just do what RonSmooth says
heres mine.



i have one 6 in booster exhausting and one bringing in fresh air
works good its at 75f

 

[Jnugg]

If the temps of the room the tent pulls it's fresh air intake from are 70°F to 75°F you'll need some serious fan power/airflow to keep temps in tent during lights on under control.

Checkout ventilation 101,it has all the info you need.My personal favorite tidbit in that thread is this graph...

Note the line that denotes a 400w HID...

the chart/graph shows that to keep an area that is equal to the footprint of the light spread 10°F above ambient temp that you would need an extraction fan that has an airflow rating (after all pressure losses from bends in ducting,long runs of ducting,a carbon filter being attached) of at least 125cfm to 150cfm...again,after all pressure losses.

At 70°F to 75°F ambient that would put you at 80°F to 85°F in the tent during lights on.80°F is okay but not ideal and on the high side.85°F is too hot and would be ideal if running a sealed environment (which is virtually impossible with tents due to tiny pinholes,+ you would need an a/c in the tent,along with dehumidifier which adds more heat when running,and a c02 tank).

Now look at the line on the graph that denotes a 400w HID.

In order to keep lights on temps in the tent only 5°F above ambient,you would need an extraction fan that has an effective airflow rating (again,after all pressure losses) of about 250cfm to 275cfm and that would give you a lights on temp in the tent of 75°F to 80°F which is reasonable.

So,to do your homework for you....get a 6" 440cfm inline centrifugal exhaust fan.