Not sure if this is the way to go...PLZ HLP

I don't know if you have to have your exhaust fan on all the time. Even when lights are off? Would a thermostat be a way, so as when the temp rises above a certain deg. it will kick on untill it levels out. But what about recirculating air every two minutes or so. Will I have to have another exhaust to acomplish that? And waht might be the order of light,fan, carbon filter. I understand the pushing of air through the carbonfilter is easier than sucking it. So I was thinking light, fan, carbon filter, then out. Any good/bad comments appreciated.

Are you talking about a cooltube or something? In that case, yes the order Light --> Fan --> Filter --> out is correct.

Also, if you have passive air intake, you need to have your exhaust fan (for your grow area, not the cooltube) on at all times. Even if you have active intake, you would need to have an exhaust fan to keep fresh air in your grow area.

I was watching a video that had some of this in it just the other day. If you have a recirculating fan in the grow area then you can certainly turn off the exhaust fan/ intake fan when you need to. For example: It's 2 degrees out and the air that gets brought in from outside needs time to warm or your grow area will simply get too cold. You cycle the intake/exhaust. As long as fresh air is introduced regularly and the air is kept circulating there is no harm in it. Mine is on all the time...

appleseed said:

I was watching a video that had some of this in it just the other day. If you have a recirculating fan in the grow area then you can certainly turn off the exhaust fan/ intake fan when you need to. For example: It's 2 degrees out and the air that gets brought in from outside needs time to warm or your grow area will simply get too cold. You cycle the intake/exhaust. As long as fresh air is introduced regularly and the air is kept circulating there is no harm in it. Mine is on all the time...

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So let me get this straight. I'm gonna need two exhaust. One for the light and carbon filter can and another for when the light fan is not on. Will I need a high cfm to move it up and out while I have a couple of small fans inside the tent? Thanks...

Michael Dee said:

what might be the order of light,fan, carbon filter. I understand the pushing of air through the carbonfilter is easier than sucking it. So I was thinking light, fan, carbon filter, then out.

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i have no idea why people think you can put a carbon filter in the middle of a run. store bought filters look like this - http://www.htgsupply.com/products.asp?categoryID=9&subcategoryID=29 - and are made to pull air through the filter. these filters have to be at the beginning :

filter -->duct -->light -->duct -->fan -->outlet.

you can run this system 24/7 to keep fresh air in the room.