Fan placement and carbon filter placement

I have everything in my grow closet on yo-yo's, I did this because in my head I was thinking that if everything was a straight shot from the fan it would maximize air flow, keep things cooler, etc... I think I ran into a problem though that I didn't think about... Should the carbon filter always be placed at the top of the room? My thought was if it was a straight shot to the fan from the carbon filter, it would pull better and maximize air flow... Thing is, I'm now having some issues with temperature.

When I first set up my closet I had my lights about 4-5ft above my plants and my fan and filter were about 5-6 ft up... I was able to keep temps around 78-79 with this... Thing is, the lights were obviously too far away, but I didn't want to adjust anything till I had more yo-yo's shipped in. Yo-Yo's came in so I then adjusted everything down to about 3ft above the plants (habanero peppers for now until I get everything ironed out in here)... After doing this I'm now dealing with temps ranging from 85-87. I have two thoughts...

1. Not enough passive intake
----- Why? When I open the closet doors the temp quickly starts to drop (my house AC is set to 72)

2. Carbon Filter needs to be up higher
----- It's sucking out some cold air and not enough hot air
----- In my head the placement didn't matter, but now I'm thinking it may help in different areas

3. Does the fan hitting the light have to go in a certain way? Let me explain... my air flow is from right to left

----exhaust<-----Light<--Fan<--Carbon Filter

---- The air from the fan is blowing on the top of the bulb and then out the other end, is it better to have the air from the fan be connected to the socket side of the air hood? so the air travels from the base of the light out the other end? I placed it this way because of the electrical cord, but if I need to turn it around I can easily do that. Just curious if it matters.


Any opinions on this? Does the carbon filter need to be up top? or is the way I have it ok? Is my issue simply not enough passive intake?



600 Watt MH in there right now, I have a dimmable ballast though. 500 CFM inline fan with carbon filter. Ducting is connecting the carbon filter to fan, and fan to light, I then wrapped ducting insulation around all ducting to control heat and noise. Everything is hanging from bungee cords and yo-yo's to help with vibrations.

Forgot to add, I'm in a closet that is 2ft deep, 7ft wide, and the ceiling is at 9ft... If that matters...

thats fine man. thats how i had mine set up for a long time

Filter at top. And filter light fan out. And bigger intake should fix your problem.

Yea, I've been thinking more and more it's just not enough intake... A lot of people had told me the closet door cracks would be enough but apparently my doors are sealed better than others I guess... I'm thinking a hole big enough to put a standard ac vent cover over with ducting on the other end at a 90 degree turn downwards to keep light from escaping. I'll wait for more opinions, but that may be my weekend project.

Your hole idea will be best. But make the duct a S or M. Not just a 90. Light getting out isn't that bad bit light getting in is.

I was actually thinking of just cutting a rectangular hole on one side of the wall, on the other side doing another hole but it being about 6 inches higher than the other hole... Removing the insulation in the wall inbetween the two so air can travel, and then ducting towards the ground on the inside wall... That would accomplish an S turn with out all the extra duct work on the inside taking up space. In theory that should work.

On a side note... I know this kind of heat isn't good for marijuana, but my habanero plant and my bhut jolokia plant really seem to like it lol.

A 4" hole in the door should be fine. And if you mount the duct to the door down low it shouldn't take up to much room. And if you cut and use the wall you could be asking for truble. Moisture can get in there and mold. So you would never get ride of it. Or you don't know if insulation is tight or loose. So it could be spread in the room.

Never thought of that... I don't really want to put any holes in the door but I guess I'm limited with options here... Still thinking on the best place to put an intake hole...

sudodaemon said:

Never thought of that... I don't really want to put any holes in the door but I guess I'm limited with options here... Still thinking on the best place to put an intake hole...

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If it's a nice door don't cut a hole in it. Go to homedepot and in the back they have damaged doors. Most already have a small hole. And you can get them for 10-15 bucks. Just make sure it's the same size. And save your old door for when you take the closet down.

Nice idea... It is a nice closet door... this house is only like 3 years old so. I'll see if I can find a damaged door or something alone those lines.

Wait a sec... a new door is only like $30 from Lowes or Home Depot... I thought they were a lot more than that... I'm not worried about $30 bucks... Fuck this door, it's getting cut up this weekend more than likely lol.

sudodaemon said:

Wait a sec... a new door is only like $30 from Lowes or Home Depot... I thought they were a lot more than that... I'm not worried about $30 bucks... Fuck this door, it's getting cut up this weekend more than likely lol.

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Lol. Interior doors are cheep.

I didn't cut the door. I was playing around more in the room and I got an idea to use an IR Thermometer and see if anything was absurdly hot and I noticed the top of my res was in the mid to upper 80's where as everything else in the room was low 80's high 70's... Seemed weird to me... that's also where I have my thermometer telling me the temp around where my plant is... I have the entire top of my res lined in foil duct tape, so I decided to use the ducting insulation I had and covered the res top with that, it's adhesive on one side and shiny on the other side. I laid that down, cut out circles where my netty pots go and turned everything back on... Been running a day since then and, well, crazy shit, my temps are fine now... I decided to line my entire res with this ducting insulation... I can throw a frozen bottle in my res and keep the temps in there stable in the 60's easily.

So I don't know if my res was giving off heat, or reflecting it, or what the hell was going on. But by me putting this ducting insulation on the top of my res my thermometers are now reading temps in the mid 70's.

Here is a look at my set-up.......overall concept and placement has worked over twenty years for me, just did this new tent yesterday. Growing a Kannuba Seed. Co. strain called "Smile" a 60/40 indica strain. If you cant keep your temps down your going to see a significant reduction in overall harvest and quality. Good luck on your grow.....learning new things makes you as better guru!

meyerjan said:

Hello .. Em Meyer.... Em new here Its Pleasure to join this community

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Welcome. But there is a introduction section. Hijacking a thread is frowned apon. So keep to the subject.