Carbon filter help - first indoor grow

I've grown 3 plants successfully outside and decide to take up and indoor grow. My grow tent is home made which I've constructed in a 6ft tall cross space. I have the room completely sealed, with negative pressure as well. I have a 600w mh/hps light with 12 babies in veg.

I purchased a brand new 6in phresh skinny filter (300-450 cfm), 6 in ducting, and a 6 in 400cfm fan with a speed controller. I've tested the room for negative pressure prior to adding intake holes and walls came in so I know negative pressure is there.

I have my fan pulling air through the carbon filter and ducting out of my 6x6 grow room near the top of the room. Filter and 1ft of ducting inside the room and the inline fan and 2 ft of the ducting is outside of the room. All connections were guerrilla taped and the clamped.
Max temp is 79 degrees. Cross space is in the basement as well.

I tested my filter with an incense and smoke and it failed both tests. Looking to flower in 1.5 weeks and in need of some suggestions. Thanks !

Incense and smoke doesn't seem to be the best way to test your carbon filter. Just because you can still smell the smoke doesn't mean it isn't functioning properly.

I've read online that people have tried to smoke in their grow room and were unable to smell it. I know my fan/filter is more than enough the size for my room, just can't figure anything out.

All you do is take the filter out, put on the pre filter and enjoy correct? You don't have to do anything to the filter itself correct? It didn't come with instructions and there were a few small chunks of carbon in the bad the filter arrived in

you know i've found that they market 6 inch fans and filters together based on price. People think they are getting a good deal. When really you should be running a 8" filter with a 6" fan. This allows the air to pass a little more slowly through the carbon absorbing more dank smell.

Just my experience.

Your other option would be to slow the fan down w/rheostat. It most likely doesn't need to be going full speed to maintain neg. pressure on your room.

bottom line, slow the air flow down and it will filter more efficiently.

Sh@man said:

Incense and smoke doesn't seem to be the best way to test your carbon filter..

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how would you test it?

Sh@man said:

Just because you can still smell the smoke doesn't mean it isn't functioning properly.

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If you can smell anything @ the exhaust it absolutely is not doing it's job.

joe macclennan said:

you know i've found that they market 6 inch fans and filters together based on price. People think they are getting a good deal. When really you should be running a 8" filter with a 6" fan. This allows the air to pass a little more slowly through the carbon absorbing more dank smell.

Just my experience.

Your other option would be to slow the fan down w/rheostat. It most likely doesn't need to be going full speed to maintain neg. pressure on your room.

bottom line, slow the air flow down and it will filter more efficiently.

Click to expand...

Roger that

I have a speed controller installed on my fan. I can run it on the lowest setting and still achieve negative pressure. I've tried all of the variable speeds as well. Would you say that smoke blown directly on the filter would smell more that say 10 plants full bloom? I'd think about the same.

Also I know there isn't any air leaking because with the insense test and smoke test the filter grabbed it right out of the air. Wouldn't running a 6 in fan at a slower speed virtually be the same as running a 4 in fan at normal speed through a 6 in filter? Thanks for the responses

If your filter is a legit brand new phresh filter and is rated at 300-450 cfm and you have a 6" fan on a speed controller dialed down and still have negative pressure, and odor is getting thru, you have a leak between the filter and fan or a bad filter. Dont think iv ever heard of phresh putting out a bad filter, a lot of the off brand filters suck but phresh is pretty reliable

No one has asked about your humidity? If your humidity is pushing 50% or higher is starts to become less efficient due the moist carbon. It will stop completely around 65-70%...which is most veg rooms. I would start there Phresh are good quality and if used with the proper inline they are one of the best...JAS

JonnyAppleSeed420 said:

No one has asked about your humidity? If your humidity is pushing 50% or higher is starts to become less efficient due the moist carbon. It will stop completely around 65-70%...which is most veg rooms. I would start there Phresh are good quality and if used with the proper inline they are one of the best...JAS

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+1. Phresh filters are awesome. I'm 6 weeks into flower with 2 plants and I cant smell them at all.

Iv never heard of a small tent with a 600 watt light in it, during veg , with a 6" fan running have high enough humidity to hinder a filters ability to filter air.

I'm lost. This is my first indoor grow and I've done my research. My filter is inside my grow room as well. The fan and 2 ft of dicing are located outside of the tent. This wouldn't effect anything would it?

I'm sucking through the filter, not blowing through and my intake is about 1.5x the size of the exhaust. I can feel current being pulled through the filter.

Other than slowing down the fan speed is there anything I can do to slow down air flow without straining the filter and fan?

I'm going to put a humidity gauge in the room tomorrow and see roughly where my humidity is at.

Also in the cross space it is rock and dirt flooring. Should I try lying down poly plastic with mayne a drain hold in the middle and sealing the floor of the grow room with guerrilla tape? Maybe moisture is sitting under the dirt and rock?

If I had a filter. I'd put mine at the bloe side. So good thing I dont..or I'd be doing it wrong lol

yeah, name brand for me this time around...I cop'd one of those cheapo cans off Amazon and still smelled some cindy...good thing it was C99 and not some skunk.....you get what you pay for

It will come down to seals or humidity...I'd put money on it! .. JAS

heres my custom built carbon scrubber matted to a 10" 752 cfm fan. its mounted inside the tent. no one can smell a thing in my house, or basement grow area. total cost for the scrubber was about 70.00 and another 60.00 for the 200 oz oz of activated charcoal. theres about 150oz of activated charcoal in the scrubber. its big, a little heavey, but does the job.

you could wrap a blanket around the exhaust which will both slow the airflow and also lower the noise. or duct out of the grow room and have your fan sitting on teh floor or on top of a pillow on the floor with a large pile of sleeping bags & bed comforters on top of the exhaust of the fan... Definitely adds some resistance to the fan.