Grow Room Passive intake vs active

[StevOrganic]

Hi guys im growing in a 4x2ft tent using an acinfintiy 4 inch inline fan for extraction with 2 small ram fans circulating the air. I notice that the tent has positive pressure even when the fan is up full whack it is slightly bulging. I have left a hole open on the bottom of the tent opposite side of the inline fan to pull air through tent passively.

My question is would it be beneficial for me to put in a small intake fan like a bathroom extractor as I am having trouble getting my lights out humidity down below 60% and I am thinking if there isnt negative pressure being created this could contribute to getting budrot as the flow of air isn't optimal. The plants are moving around nicely with fans and temp is 69f lights out humidity staying around 60-65%. I am entering the last couple weeks flower.

 

[WildBill]

I'm confused! How do you have positive pressure in a tent when you use a fan for extraction? Extraction means to remove.
For proper air flow and heat extraction, you remove air from the top and have air intake(passive) available on the bottom.
The only way you can have positive pressure in a tent is by blowing air into the tent.

 

[StevOrganic]

I'm confused! How do you have positive pressure in a tent when you use a fan for extraction? Extraction means to remove.
For proper air flow and heat extraction, you remove air from the top and have air intake(passive) available on the bottom.
The only way you can have positive pressure in a tent is by blowing air into the tent.

Well maybe I don't have positive pressure but tent is slightly bulging even though I have fan venting the air out into attic.. what would be the reason for this so? Could this just be caused by the 2 circulation fans blowing air around the tent?

 

[MesaBoogie]

I have fan venting the air out into attic

Sounds like a recipe for mold.

 

[StevOrganic]

I know it seems that way but the air circulation is very good but I am just wondering would the active intake be more beneficial than a passive intake in ensuring a good flow of air through the tent?

 

[StevOrganic]

I have done 2 auto grows and have tent set up o

Sounds like a recipe for mold.

I have done a year of growing so far venting into the eve of the attic and just one month ago I thoroughly inspected the area where the air is venting and zero sign of any mold or moisture on wooden beams or surrounding area.. its only a 4x2ft tent with 2 plants hardly enough moisture to cause mold in an attic that has fresh air passing through it

 

[WildBill]

Well maybe I don't have positive pressure but tent is slightly bulging even though I have fan venting the air out into attic.. what would be the reason for this so? Could this just be caused by the 2 circulation fans blowing air around the tent?

LOL! No idea my green brother! Does it bow out ALL the time?
You're not a Scott, right? You didn't get the direction wrong? LOL! Just kidding!
No, circ fans won't cause that. I assume the fan is an axial flow fan. There are inline fans that are not axial flow and are VERY inefficient.
Now, grasping at straws, what is the airflow in the attic? Can air come into the attic by different wind patterns with windows open in the room or house?

 

[blue]

You didn't get the direction wrong? LOL! Just kidding!

Not the craziest suggestion i've ever heard!

I would check to see that the air is actually blowing out of the tent from the top. If not, then it's sucking air into the tent which would cause positive pressure.

If you do feel eair blowing out the top (being extracted) it should feel warm and a decent gust - if that's not happening, then you could do with a better (more powerful) out take fan.

Having an intake fan for a tent that size certainly won't help.

Another sign that you may have got the configuration setup wonky is that you will have a very strong smell of flowering dope in your grow room (as it won't be being sucked through the carbon filter / cleaned of smell and extracted.)

Hope this helps
Blue ^_^

 

[StevOrganic]

Not the craziest suggestion i've ever heard!

I would check to see that the air is actually blowing out of the tent from the top. If not, then it's sucking air into the tent which would cause positive pressure.

If you do feel eair blowing out the top (being extracted) it should feel warm and a decent gust - if that's not happening, then you could do with a better (more powerful) out take fan.

Having an intake fan for a tent that size certainly won't help.

Another sign that you may have got the configuration setup wonky is that you will have a very strong smell of flowering dope in your grow room (as it won't be being sucked through the carbon filter / cleaned of smell and extracted.)

Hope this helps
Blue ^_^

Thanks guys oh believe me first thing I checked was the direction of airflow well a certain amount of air would get into the attic through the eves and I also have the little flap open at the top of window in room where the tent is set up which is a small box room. Have specs of fan below im sure there is enough power for the size of tent with short ducting that only has one bend.

I do have a attachment on the end of ducting to direct the air flow into the eves of attic im not sure if this could disrupt the flow of air?

I also have a sleeve on the carbon filter which is a 4 inch Rhino Pro could this sleeve being a little dirty disrupt the airflow?

 

[Arthur]

Your tent should be sucked in. I loose 4" on a side when the extractor running 100%. If your not pulling in the walls of the tent, your extraction fan is too small or there is an issue with the unit.
Left as it is, your gonna have mold/rot issues... maybe not this round, but it will happen. Some genetics are more resistant, but needs to be addressed.
It's too late at this point, but there is a product that I tested last fall out of Canada called Rotblock. It works... but needs to be used from flower initiation. Went all thru flower with silly high rH #s, no issue.