Grow room exhaust while maintaining humidity

Lion-O said:

Just setup an hps 600w vented light. Right now I have a 6" duct coming from an adjacent room, running through the light and into the grow room. I know it should vent outside and there are 2 windows available for that. However, I'm trying to increase humidity with a humidifier right now. Soon the smell will be strong and the room will have to be vented outside or a 2nd fan purchased with a carbon filter.

(Currently) 2nd room ->light->fan->grow room

(Proposed) 2nd room->grow room. light->fan->outside

(2nd proposal) 2nd room->grow room->splitter w/removable cap->light->fan->outside

The benefit I see with #2 is it's easy to shut off room exhaust, but it hinders fresh air intake.

To minimize expenses, I'm trying options using the single fan. However I don't see how I'll keep high humidity while sucking air out of the room to the outside. I understand high humidity is only desirable in veg.

Thanks for any input!

Click to expand...

justugh said:

all this is easy

u have 1 light correct .....if so then it is this

carbon filter (hanging in the tent in the center ) ducting ) then the cooltube then ducting off the back of the cool tube going out of the tent to the fan then a 2nd set of ducting off the back of the fan to ejection point outside

so carbon filter ....ducting .....cooltube....ducting......fan.....ducting......ejection point
this is the most effective way of running it the tent maintains negative pressure when it is closed (smell control) ........the carbon filter sucks in the hot used air in the tent then passes it over the hot light cooling it then pass the fan dumped outside ......just hot air (use a portable ac window kit it looks like u have a portable ac in that room)

as for the RH in the tent .........with this kind of set up u need to control the intake air ........keeping that cool will keep the tent cool this also applies to RH .......so 2 ways to do this
1 u control the outer room where the air is drawl in for the tent (u have to keep the whole room at that lvl to make sure it stays
2 u place a humidifier in the tent directly

but look into a ultra sonic humidifier .......it is digitally controlled so u can set pretty close to what u want (this is copy and paste of something i wrote a day or 2 ago

the standard ones will not put it out in a way that will work for u(it passes out to quick) .......u need to change over to a ultra sonic
http://www.amazon.com/Homdox-Ultrasonic-Humidifier-Constant-Nightlight/dp/B01264ZIYU

it is not like the normal ones this little 3 inch disk in there vibrates at a high enough lvl anything liquid that touches it mists up .........with a cool mist setting u will raise the RH in the tent the system is digital so u will keep that lvl with in 5 % or so (little tweaking u will have it mastered)....the warm mist will make it rise up need your ejection point for tent ....the cool mist will keep it low to grow and will raise up as the temp of the air does it is in so will make a cycle going mixing with intake air

i use one of these in my drying tent to hold it to lvl for me like a giant humidor


get a speed controller for your fan ............if u can keep the intake temp cool u can run the fan slower so it humidifier will keep the lvl u want and the tank will last longer .........if the temps are getting hotter in there increase the speed of the fan moving more air leaving less time for i to heat up making it cooler .....u are just going to be filling the tank every 36 72 hours

this is based off my own playing around with a 4x4x6 and 600w ....2 600w and a 1000w
400 cfm inline fan ....carbon filter
600w intake to exhaust full power 6 degree diff between them .....half power u are looking at 11 degree diff

keep the plants below 80f (higher thc counts....... thc degrades faster onto other chemicals at 80 and above)....bud lvl above the light it does not matter it is under that counts

Click to expand...

Lion-O said:

Thanks, but it's not a tent but a whole room. No A/C installed at present, but I stated I have access to one if needed can install later. It's not a cooltube, but an air cooled light, but the idea I believe is the same. I have a warm mist humidifier in the grow room right now, so you say an ultrasonic will run longer without refilling? If that's the only issue with the humidifier, it's not really a big deal as I have access to water nearby. I do have a speed controller for the fan installed right now. For your proposed setup the filter would not be necessary as I have my own house, on several acres, and the grow room is facing the back yard as well. No neighbors next door or behind.

I reconfigured the setup so it is now:
external room -> grow room -> light -> fan -> window

So right now the grow room has no exhaust to outside. So the question remains if I can or cannot have exhaust and intake work with a simple splitter or if I were to detach the external room connection and make it simply passive, and have the then open end of the light serve to exhaust the room when it comes time to flower, which would be best?

Click to expand...

justugh said:

change it the way u have is horrible bad

1 the air in the grow room need to exchange unless u are offering it Co2........no co2 the plants are suffer lose of power will not do as well for u

2 the hot air in there will build up stressing your plants (hot makes the plant cycle water to the leaves not the flower building the sites)

3 the old humidifier raise (the water vapor the ultra sonic has a cool mist mode this will make the RH collect low and it will raise up as the air the water is in gets warmer ) the system u have now kicks it out hot the RH raise to the top of the room and falls as it cools but since u have a HID in there cooling is not going to happen like it does in a regular room


u need to remove the hot used air in the room u are ......set it up like it was in a tent .......if u do it now u will see the effect in 5 to 7 days as your sucking in more Co2 to the room the plants will grow faster and bigger u can almost swear u see it grow 2 inches in a day (during the stretch)

but that is one of the main rules with growing weed .....no co2 adding in the air in the area needs to exchange completely once every 5 mins (personally i like a quicker time once every 2 mins) ......done right the Co2 will pool up in the room as it is negative pressure

co2 is a heavy gas Oxygen is lighter ............think of water and oil co2 is water and oxygen is oil
during your light hours the plants are craving Co2 for building powering ......when the lights go off they are looking for Oxygen

Click to expand...

Lion-O said:

Didn't hear back, so I have the grow room exhausting from the light to outside now. Don't have a second fan so I've got the hose from the 2nd room going to the back of the circulating fan in the grow room. Removed the humidifier from the room.

Shouldn't the intake between rooms have a fan? Even with the grow room door shut I didn't feel much if any air movement at the hose between rooms, that's why I temporarily have the hose placed behind the circulating fan. Thanks for the assist.

Click to expand...

Lion-O said:

Thanks justough, as well as the others who commented. No 2nd fan will definitely save me some coin, which is good since I'll have to buy a usb microscope and a vaporizer soon as well. 1st grow...

Click to expand...