New Grower Ventilation.

[longball]

This is the formula I have found in numerous places to calculate what size fan one will need. Example on left. My tent on right.

LxWxH / 5 min

10'x10'x10' / 5 Min --------2' x 2' x 6' / 5 min
= =
1000 ft^3 / 5 Min ---------24 ft^3 / 5 min
= =
200 ft^3 / Min ------------4.8 ft^3 / 1 min
= 200 CFM = --------------4.8 cfm


So I will need 4.8 CFM doubled since I will be going through a carbon filter. Why do I need a inline fan that is way way way more powerful than the formula suggests? Am I missing something? Please help!!

 

[Muddy]

A lot depends on what type of lights you are using. HPS, with the heat they put out, requires a faster turnover than LEDs or CFLs. For a 2' x 2' x 6' tent, that's 24 cubic feet. A 4" in line fan rated at 168 CFM like this one, http://www.plantlightinghydroponics.com/active-air-165-cfm-in-line-duct-fan-p-2755.html, is capable of turning the air over in that space 7 times a minute. (168 / 24) Adding a carbon filter will reduce the flow a bit, but not to the point where a larger fan would be needed. My suggestion would be to use a 4" inline fan and install a variable speed controller. Then you can slow down or speed up the fan as needed to maintain proper temperatures in your space.

 

[low_and_slow]

Also consider that too much suction on a tent can pull the walls in and cause them to touch the leaves of the plants...I struggle with that because I have a monster fan to cool an HPS light. When the walls touch the leaves, it causes a bleach spot where no photosynthesis took place during the day, basically just yellows off and you're down 1 solar panel the plant needs to make THC!