I have a ventilation question.

My grow tent is in a small walk in closet. The tent is ventilated with 4 inch ducts and a lower cfm fan blowing in, and a higher one with a carbon filter sucking out. My tent walls are not sucked in or blown out, I have it balanced quite well. Cold air is sucked in from outside of the closet into the tent, but vents the warm moist air into the walk in closet. The walk in closet is vented through a 390CFM 6" exhaust fan. I only had a 4" carbon filter so I stuck that on, so it is filtering for a second time. Excess air is sucked into the closet from around the doorframe, there are big enough gaps, and it helps the 4" fans as well with airflow as well I think.

That has been working fine but I am trying to control humidity better during flower. I purchased a dehumidifier and I have it placed inside the walk in closet. It is generating excess heat and getting hotter than I like in there. I have removed the carbon filter for now out of the closets exhaust fan and that is keeping it under control.

I purchased a new 440CFM 6" fan with a bigger 6" charcoal filter. My idea is to replace the existing exhaust fan and filter with this one, I am not sure how much the carbon filter will slow it down from 440CFM but I am guessing if I use my 390CFM down the line just before the vent exhausting as well, I will have better performance than just the 440CFM and carbon filter without the extra assistance. Does that sound logical? I am trying to get away with avoiding cutting another hole in my wall for intake vent, and put the slower fan to use. I am pretty sure the charcoal filter will slow the 440 down below 390, and it would make sense to have the 390, and it will increase my flow to at least 390, 400 if I am lucky?

where are you pulling you intake air from?

otrov31 said:

where are you pulling you intake air from?

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Air comes from bedroom to tent. Thet to closet closet to bedroom.

So where is the second exhaust fan venting to? Is that just being used to scrub the air without actually 'venting' it? I'd say using the small closet as your breather room will just end up causing problems. Breather rooms need to be fairly large and have decent flow of their own. Why not just use a single extraction going directly from the tent, to the outside of the closet. You can use a louvred vent or slotted grille to make it look neat and inconspicuous. If your walls aren't being sucked in, you don't have negative pressure and once flowering kicks in proper you could find yourself in a very smelly situation!

HighFlow said:

So where is the second exhaust fan venting to? Is that just being used to scrub the air without actually 'venting' it? I'd say using the small closet as your breather room will just end up causing problems. Breather rooms need to be fairly large and have decent flow of their own. Why not just use a single extraction going directly from the tent, to the outside of the closet. You can use a louvred vent or slotted grille to make it look neat and inconspicuous. If your walls aren't being sucked in, you don't have negative pressure and once flowering kicks in proper you could find yourself in a very smelly situation!

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Yeah basically cold air from bedroom gets sucked into tent, filtered and dumped into closet, all that air and more supposed to get sucked out of the closet filtered, and dumped into the bedroom, but in a different part of it. There is an AC in the bedroom. My issue is my closet is getting a tiny bit too hot. I have no smell issues untill removing the second filter for airflow, but now the heat is managable.

I was just thinking if this current fan is 390 and keeping up without a filter, a 440 fan with a bigger filter should keep up. I am not sure how much slower it will be after adding a filter, I am guessing it would be slower than 390 so the second fan assisting should at least perform as good as just the 390 with no filter right?

I guess I will find out, it is ordered and will be here in a couple of days i hope. Right now my whole house smells like pot lol

what type of lights are you usinig and how are they cooled?

otrov31 said:

what type of lights are you usinig and how are they cooled?

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SF-4000, I have a window fan pointed at them lol. Tent is cool, it sometimes touches 31, but for the most part like now it is sitting at 28, depends on how hot it is. Temps are ok because I use CO2.

I would also like to report that fan blows a lot more air and has a lot more torque than the old fan, and it alone has taken care of the heat problem. I watched it drop from 27.3 to 25.8 and it is still dropping.

you said that you have an ac in the lung room.. can't you drop the temp a little in there?

otrov31 said:

you said that you have an ac in the lung room.. can't you drop the temp a little in there?

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I want my temp between 28 and 31 in the tent because I use co2. I have the AC set to 20 in the bedroom. I have dropped it down to 18 before but I don't think I will need to with this new fan! I love it! The charcoal filter is also huge compared to the old one.

do you know how much CFM you filter is rated to?

otrov31 said:

do you know how much CFM you filter is rated to?

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No but it came with the fan, the last filter was for a 4" I threw on a cheap 6". The new fan with the filter moves MORE air than the old one without!

you should then move air directly to the bedroom in my opinion ... that would be the only way.

so it get colled in the bedroom, and than comes back to the closet already cooled.

otrov31 said:

you should then move air directly to the bedroom in my opinion ... that would be the only way.

so it get colled in the bedroom, and than comes back to the closet already cooled.

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The tubing would be very in the way in the small space I have. This little middle area in the closet works kinda well now. It captures a bunch of the moisture right away and it also catches any leaking smells. Its under control now I would like it around 20 in there but its 25. Its also 25 at a high spot and I can feel the cold floors so its alright. Winter will hit soon and it would be all good.

Distortionist said:

The tubing would be very in the way in the small space I have. This little middle area in the closet works kinda well now. It captures a bunch of the moisture right away and it also catches any leaking smells. Its under control now I would like it around 20 in there but its 25. Its also 25 at a high spot and I can feel the cold floors so its alright. Winter will hit soon and it would be all good.

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How do you inject your co2? Do you have a meter to test ppm?

ÒÒlegilizeitÒÒ said:

How do you inject your co2? Do you have a meter to test ppm?

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Yes, your co2 controller seems fancier but yeah, i set it to the ppm i want and it will turn off the regulator when it is reached. For my co2 setup, your regulator is better as well, I took my fish tank co2 setup so it uses bubble counters made for very slow release. It is hard to estimate a proper amount to release, I had to play with it for a while where it gets to the ppm I want in good time without overshooting or taking forever.