Hello Nate!

How many CFM is your exhaust fan rated for and how tall is your tent? Do you have any oscillating fans in the tent? Does your tent have any of the 6"x12" screened windows near the bottom of the tent.? If yes I would open one of those up.

Shad

Shad said:

Hello Nate!

How many CFM is your exhaust fan rated for and how tall is your tent? Do you have any oscillating fans in the tent? Does your tent have any of the 6"x12" screened windows near the bottom of the tent.? If yes I would open one of those up.

Shad

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Tent is almost 6' tall. I have a static fan, not oscillating. Screened window already open about 25%.

I'll look at the AC Infinity book to find CFM. As posted originally, the airflow is excellent if the charcoal filter is disconnected, so I'm wondering if these filters always choke air flow this much, or if mine is clogged/defective?

Thank you

Nate_in_AK said:

Tent is almost 6' tall. I have a static fan, not oscillating. Screened window already open about 25%.

I'll look at the AC Infinity book to find CFM. As posted originally, the airflow is excellent if the charcoal filter is disconnected, so I'm wondering if these filters always choke air flow this much, or if mine is clogged/defective?

Thank you

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Yeah the exhaust fans tend to lose about 15-20% efficiency with the charcoal filter connected, basically you need to buy one a little bit bigger than what your space needs. Assuming you have a 2x4x6 grow area = 48 cubic feet. To get it a little bigger I will multiply by 1.33 so it is a third bigger. 48x1.33 = 63.84 CFM fan minimum needed to properly extract your tents air with a carbon filter.

I would also opt to add an oscillating fan somewhere in your tent to mix around the air a bit better and preventing hot spots. I have a 4x4x8 tent with a 203 CFM exhaust fan and charcoal filter and 2 oscillating fans, one placed below the canopy, and one above. My 203 CFM exhaust fan is just barely enough, working at 100% all the time. With the charcoal filter off I get a slight negative pressure with one of my screened windows completely open and sit at around 24-26 Celsius at lights on and 19 Celsius at lights off.

The charcoal filters usually last around 6months-1 year depending on what you put through it. Most come with a pre-filter that you slip on top of the carbon filter. If yours has a pre-filter I would recommend you throw that in the washing machine about once every 2 weeks. I noticed that after a week or so the tissue gets a little clogged and prevents proper air flow through my exhaust fan. Every day I try and put my hand in front of my exhausts exit ducting to make sure that it is pushing enough air out and if not then I know I need to clean my pre-filter.

I am also a new grower so my information may not be an exact science but can share my experiences and hope to help people learn from them.

Shad

Nate_in_AK said:

I have a little 2x4 grow tent with a "900W" Phlizon LED lamp. The grow room temperature is 68F, but I have a hard time keeping the tent at 75F or lower. When I turn on the BLOOM lights, the temp goes up to almost 85F. I have an exhaust fan (AC Infinity) sucking through a charcoal filter, set to 100% maximum fan speed. The airflow through the filter is quite low. I have no experience with these charcoal filters, is this normal? If I pull the exhaust hose off the filter, the fan moves a LOT of air.

I have one tent flap about 25% open, the tent does NOT achieve negative pressure (walls sucked in).

I'm in a legal state, and my wife is supportive of the grow, as long as I don't saturate the house with cannabis smell. I have to manage odor somehow. I can run without the filter a bit longer, but these plants will start flowering soon. I've read the really start pumping out the aroma once the flowers bloom?

HALP

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With LED lights you want the tent to be right around 82 degrees. LED's do not heat up the leaf surface like HPS. Take a look on youtube for Black Dog LED's they do a great job of breaking down the differenced. The high temperature does help IMO.