# New grow room setup plz take a look :-)



## Sparkie (Feb 9, 2013)

Hi all

I have just completed a 1.2 m grow tent setup, I have built around the outside a 1.3m timber stud frame to keep in the heat & hopefully smells to, I have a 100mm 4inch intake fan from outside the stud frame to inside the tent, I have a 150mm 6 inch out take fan n carbon filter to above the tent but not outside the stud frame which is also fully ply boarded, I then have another 100mm 4 inch fan from above the tent to the outside world, I also have a 150mm 600w cool shade light wired into a digital central heating/hot water controller for lighting which also controls my last mentioned extract fan, I purchased off eBay a digital heat/cooling controller which is set at 28 degrees, if drops to 27 a 55w tubular heater kicks in, if gets to 29 degrees it kicks in my 1st & 2nd mentioned fans, I also have 4x socket outlets for 24hr power to control my hydroponics water pump,nutrient heater oscillating fan & circulation pump.

My question is fellow growers 

Does it sound like I'm heading in the rite direction?
Does it sound like iv been extra clever in the way I have wired & setup my grow room?
Is there anything else I should have or change?

Please give me your feedback on anything you have read

Much respect people

Thank you


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## 4u2sm0ke (Feb 9, 2013)

I wouldnt be adding walls to keep heat in...


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## BackWoodsDrifter (Feb 9, 2013)

I be dence as a stump soaked in stream water fur a week pilgrem so ifin yual can at some point post some pics be able to give ya pinion from the bushline  Hope yual do well yur trails travlin pilgrem

BWD


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## Sparkie (Feb 9, 2013)

4u2sm0ke said:
			
		

> I wouldnt be adding walls to keep heat in...




You would do if ya knew what country I live in pal


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## The Hemp Goddess (Feb 9, 2013)

Are these computer fans?  IMO, you are going to need at least one decent centrifuge type fan, to go with that carbon filter.  In addition, fans are for more than cooling your space.  Your plants need a continual supply of fresh air all the time the lights are on for proper photosynthesis.  So at least one fan should be exchanging air all the time you have the lights on.  You want negative pressure in your tent--this is what helps keep smells contained and directed to somewhere it doesn't matter or a filter.

I also don't quite understand what is controlling your light?  

I think that you are making this a little more complicated than it needs to be.


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## Sparkie (Feb 10, 2013)

The Hemp Goddess said:
			
		

> Are these computer fans?  IMO, you are going to need at least one decent centrifuge type fan, to go with that carbon filter.  In addition, fans are for more than cooling your space.  Your plants need a continual supply of fresh air all the time the lights are on for proper photosynthesis.  So at least one fan should be exchanging air all the time you have the lights on.  You want negative pressure in your tent--this is what helps keep smells contained and directed to somewhere it doesn't matter or a filter.
> 
> I also don't quite understand what is controlling your light?
> 
> I think that you are making this a little more complicated than it needs to be.




All 3 fans are extraction fans , 6 & 4 inch fans would be some massive computer fans, i have created a negative pressure by having a larger 6 inch extraction fan to my 4 inch intake (fresh air fan) my central heating controller is bringing on my lighting system for instant 20hr on & 4hr off!! Simples


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## Sparkie (Feb 10, 2013)

My fans are also kicking in every 4-5 minutes for approx 2 mins everytime for a good exchange of air which keeps my humidity to around 55-60

& carbon filter also in there to,


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## The Hemp Goddess (Feb 10, 2013)

Many computer fans are 4".  I still don't really know what you mean by extraction fans.  What cfm do they pull?  I like to exchange my air a couple of times every minute.


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## Hushpuppy (Feb 11, 2013)

It sounds like you are having to deal with very cold incoming air? If so then I understand you having to ballance heating and cooling your space. Normally most indoor grows are having to deal with building up too much heat and are constantly trying to remove the heat.

I have cold air intake issues that I have to keep up. Like you, I have a room with my grow tents inside so that I can draw air into the room where it can be heated some before being pulled into the grow tents. I also have to ballance that warming with the heat generated by my lights. Its tricky but very doable. 

Are your "extraction" fans centrifugal type fans that draw air like a vacuume cleaner blower? or are they just propellor blade fans that have air space around the fan. If they are the prop type then you will want to look into getting the centrifugal fans for dealing with summertime heat as the prop fans don't create vacuume, they only push air. The centrifugal fans are much more efficient at removing heated and depleted air because they pull air rather than pushing it. If you are in a place that doesn't get much in the way of hot summer temps then you may be in good shape like you are.


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## DrFever (Feb 11, 2013)

to much cold coming in  will only cause major issues  mostly condensation   which can lead to  mold  etc    cold fronts  hitting warm fronts = perfect storm


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## Hushpuppy (Feb 11, 2013)

I don't have any trouble with it myself. I have small intake holes in the floor of my building and I control how many of them are open to allow x amount of air intake while my exaust fans are pulling the hottest air out of the bldg through my tents and lights. I have found that the winter air typically has less moisture in it even when the humidity is high, so when it comes into my building and warms up with the heated air, its humidity level drops and by the time it gets into my tents it is only about 40%Rh in 70ish degree air.


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## trillions of atoms (Feb 11, 2013)

put up some pics...


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## DrFever (Feb 12, 2013)

Hushpuppy said:
			
		

> I don't have any trouble with it myself. I have small intake holes in the floor of my building and I control how many of them are open to allow x amount of air intake while my exaust fans are pulling the hottest air out of the bldg through my tents and lights. I have found that the winter air typically has less moisture in it even when the humidity is high, so when it comes into my building and warms up with the heated air, its humidity level drops and by the time it gets into my tents it is only about 40%Rh in 70ish degree air.


    Are these  holes in your floor  directly  outside  air ???? for instance i have a room  with  two 4" holes on one side of wall and two 4" holes   on other end  of room, ( Passive air in ) straight outside air  if outside temps were  42 below  that is what would be coming in the room  from one side, other side is 1600 watts of exhaust power.
and what i found is floor and walls  from air in  side were soaked  condensation build up  enough as  Black mold started growing on cinder blocks and concrete behind the panda film
 since building a hot box meaning a thermostatically controlled  shed  to allow  cold air to warm up a little prior to  entering  room , on my passive side   condensation   Stopped  floors and walls dry  problem solved 
 doesn't matter if out side RH is low  once cold and hot meet   there is Rain  just look at the weather station  where cold fronts and warm fronts meet  this is what was happening in my room and probably many other grow room with direct outside air  in colder climate areas


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## pcduck (Feb 12, 2013)

Just like a glass of ice tea on a hot day, there is condensation.

Condensation will occur where the air molecules are slowed down enough to come together and form moisture.

The colder the outside air and the warmer the inside air the more condensation will occur. I call this the condensation line, this can easily be seen on a propane tank that is being used on a hot day.

HushPuppy's big advantage is mild outside temps and whatever condensation occurs is most likely draining down his duct work as he is pulling from the floor. If he was pulling fresh air from his roof, gravity more then likely would drain this into the lights. just my$0.02


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## Hushpuppy (Feb 12, 2013)

Hey guys I don't have any pics to show my setup but I will take some tomorrow and post so that you can see it. 

My holes are in the floor of my building and connect to outside air that is under the building. The air that comes into the building through the holes is the same temp as outside(in the winter) and about 10degrees cooler than outside air in the summer. I don't have any of the sweating issues that yall have seen. 

I understand the sweating and "dew Point" of warm vs cool air and the warm/cold fronts. My winter temps and humidity vary greatly here in NC, some days it 60 and the next its 35. It can easily go from 26 over night to 65 in the daytime. I think the key to mine is that there isn't a hard warm/cold line anywhere within my building. The key to the sweating glass is that the glass is cold and the moist air is warm, so that when the warm moist air contacts the cold object its temp is dropped below its dew point, which in turn causes the moisture to precipitate out of the air mass.

For my situation it is the opposite. I am injecting colder, (relatively)drier air in into warmer, dryish air(30-50%). It may be that my internal air is even dryer than that but for the outside air bringing in enough moisture to raise my humidity to present levels. 

DF("doesn't matter if out side RH is low once cold and hot meet there is Rain just look at the weather station where cold fronts and warm fronts meet this is what was happening in my room and probably many other grow room with direct outside air in colder climate areas")   You are looking at it backwards. If the cold airmass is at 100%humidity, regardless of its temperature(relative typical environmental temperatures), if it is injected into a warm airmass at any temp(within typical environment temp range) with a RH of less than 50%, *it will not cause precipitation*. The reason is that the heat energy in the warm air will mix with the cold air and the total air mass will settle to a temperature that is lower than the original warm air temp but higher than the original cold air temp. While the warm air will contract some, at 50%RH it has enough room to contract without reaching saturation. At the same time the cold air will expand from the heat energy, which will cause its water holding capacity to increase which will lower its relative humidity (which already has less water in it because it being cold can't hold as much water as warmer air). 

Now if you were injecting warm moist(75%RH) air into cold air that is at 50%RH then you would have a condensation issue as the lowering of the net air temp would mean less water holding capacity for the already high RH warm air. You have to look at it in terms of capacity and saturation of the air masses and the amount of difference between the two air masses.


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## Sparkie (Feb 13, 2013)

I'm using my iPad & my picture sizes are to big to upload :-(

My 6" exhaust fan pulls 552 m3/h  and my intake is 325 m3/h my current outside temp is -4 degrees c my room temp is 10 degrees c and my room outside the tent but inside the ply boarding is 20 degrees c my grow area varies from 27 degrees c to 30 degrees c depending on if and when my fans are running thru my temp controller, I run a hydro setup 4 pot, I have a small fish tank pump circulating the nutrients in the res with an air stone and fish tank 100w heater to keep the nutrients warm, my r/h is currently 35, how's this sound senior growers?


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## Hushpuppy (Feb 13, 2013)

That all sounds solid. The grow temps can be a bit lower. I wouldn't allow it to go higher than 28c in the grow area and ideal temp would be around 24c. And you want to maintain about 18c in the hydro tank but don't let it get any lower than 15c, no higher than 20c.


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## Sparkie (Feb 14, 2013)

Cheers for the info hush, my ph is currently 4.2 will this have any bad effects on the plants? I would top up the res to bring the ph up to around 5.4 ish but it's pretty full at the minute


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## The Hemp Goddess (Feb 14, 2013)

Sparkie said:
			
		

> Cheers for the info hush, my ph is currently 4.2 will this have any bad effects on the plants? I would top up the res to bring the ph up to around 5.4 ish but it's pretty full at the minute



Yes.  If your pH is at 4.2, you might as well be running straight water.  At that pH level, the nutrients are not available to the plants.  It is critical with hydro that you keep your pH levels between about 5.3 to 6.0, with 5.8 being what most strive for.  I do like a little drift, but 4.2 is way way too low.  You need to correct that now.  What do you use for pH up and down


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## Locked (Feb 14, 2013)

I am with THG, you need to adjust your ph up as soon as possible. 4.2 is ridiculously low. I don't do a lot of hydro but I do know you need ph up and down, a good ph meter and a ppm meter.


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## pcduck (Feb 14, 2013)

HushPuppy... Rh has nothing to do with condensation. Even in an area with 10% Rh you still will have condensation when cold meets hot. The only thing a low Rh will do is evaporate the condensation faster. Just like when you are outside working and sweating. A high Rh and the sweat will not evaporate it drips off you, a low Rh you still sweat but it gets evaporated before it is dripping off ya. Good air movement will evaporate condensation. Or maybe I am wrong and a glass of ice tea does not sweat in Arizona.

The rain is evaporating before reaching the ground, but it is still there.


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## Hushpuppy (Feb 14, 2013)

Relative Humidity has a lot to do with condensation as it is a measure of moisture in the a given body of air at a given temperature. Condensation will only occur when an air mass reaches saturation at its given temperature(Dew Point), condensation will only occur when cold meets warm if the cold is at or below the dew point of either air mass. If the air mass is at saturation(100%Rh) then regardless of how much air movement you have, you will not get anymore evaporation, and if the temp of the air doesn't drop below the dew point temp you will not get condensation either.

The reason the glass of iced tea sweats is because the temp of the cold glass that is sitting in the warm air is below the dew point temp of the air. If the glass of tea sits in the air mass of Arizona long enough, it will stop sweating. That isn't because it has condensed all of the moisture out of the local air. It's because the glass has warmed to the point that its temp is above the dew point of the air mass that it is sitting in.


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## Hushpuppy (Feb 14, 2013)

I understand what you are saying. If I had really cold air coming in through metal vent pipe or something similar and that pipe was exposed to the warm air mass within my building, then it would be likely that it would sweat because the cold air coming in would make the pipe cold. If that pipe is exposed to the warmer air that has sufficient moisture in it (and if the temperature of the pipe is lower than the dew point temperature of the warm moist air, then any moisture that comes in contact with the pipe will condense onto the pipe and run down into my building. This is exactly how a dehumidifier works. It makes a set of coils cold enough that any air passing over the coils(with enough moisture present to have a dew point above the temperature of the coils) will produce condensate on the coils.

The key here in my space is that I don't have any metal pipe extending into the warm airspace that is cold enough to cause condensation. I have wood floors with holes drilled into them where the air is sucked in from the outside. Even though the air coming in is cold, the warm air mass doesn't have  enough moisture in it for the intrusion of cold air to cause any condensation. If the relative humidity was high enough in the building then the cold air that is jetting into the space would constantly shoot a streem of fog from the holes in the floor as the cooling would cause cloud to form.

The 3 pics show the holes which can be closed down to just 2 holes or opened to 5 holes when I need more air flow. The holes are each 2.5" in diameter.


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## Sparkie (Feb 15, 2013)

Hi, cheers for that, I got ph down & a good reliable digital ph test pen, I must of slightly over done it with the ph down, I res is literally full so can't add more water, I been out and bought some ph up so now turned off my water pump until I have the ph at the correct level, what level do you suggest it should be folk ??


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## Hushpuppy (Feb 15, 2013)

5.8-6.0 is ideal for hydro but almost always as the plants use water and nutrients, the PH changes over time. I like to set my PH for hydro at 6.2 and allow it to fall to about 5.0 as the plants take in nurtrients, then adjust it back up again. Others like my Bro use different nutes and their PH rises over time, so they have to start lower (around 5.5) and allow it to rise across the sweet zone until it gets above 6.0 then reset it back down.

You will need to adjust it to as close to 5.8 as possible and then watch it for a day or two to see which way it "drifts" and adjust accordingly.


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