Can I vent this?

[cypher420]

Hey so this is my first grow and i wanted to buy this Grow Tent and 400w HPS kit but i'm not quite sure how to set up the ventilation. is it ok if i just set up small cfm fans without ducting? i don't want heat to be an issue, but at the same time i want to keep it as cheap and simple as possible since the tent and light were pricey enough :)

any help or tips appreciated!

cheers

[cypher420]

BUMPED

Sorry need help pretty quick, my plants are ready to flower but the room I have set up right now can't be completely dark. So i'm heading out today to get my tent and new light.

With money being tight ventilation is still a problem. Because the light i'm getting is not made for cooling i'm purchasing a cool tube as well. So far i'll be getting the Air Cool Cylinder Reflector 20'' has 6" opening, Inline Fan (Active Air) 6" 400CFM attached to flexible ducting for exhausting the light heat, and an oscilating desk fan for plants.

is there anything else i need? I'm assuming I will need another exhaust for the entire tent, can i just use an Active Air Exhaust Fan 265CFM w/ 4" Intake (its shaped like a squirel cage fan) without any ducting? I know i'm missing a scrubber or carbon filter but at this point i'm spending soooo much money i just want to get it started and i'll worry about that later heh.

So let me just reiterate i am brand new to this whole thing, everything I have listed is all i have/know about so if i need more or special ways of putting it together please don't hesitate to let me know :)

[SpaceNeedle]

Ok, you are 80% there. Your light and fan with the hood will work fine.

Now ventilation for your tent. For $10 you can pick up a summer fan at your local thrift store, and place it in the tent. It would also be imperative for you to leave the tent open a bit so the poor buggers will get some fresh air. Then you will have to monitor the temp inside your tent with the light ON. I would try it without plants in there and just see what the temperature will build up to in there, with just the circulating fan inside the tent, and the vented light working its fan. If it goes higher than 80F or 85F, you will need to change that. This is the cheapest way. If you are getting temps in there in excess of 85, you will need another inline fan about the same as you have for your light. You will need to make a 6" hole near the top, put your fan in there and EXHAUST the warm air out of the tent.... to preferably out of the house. Near the bottom of your tent you will need to cut another hole 3x the size of the EXHAUST you cut at the top to bring fresh air in. This bottom hole is what's call a passive INTAKE and you do not need a fan for it. If you don't want to cut a hole that size, you can make it the same as the exhaust hole (6"), but that would require a second fan to bring the cooler and fresh air into the tent. In other words you are exchanging the air inside the tent constantly, one fan pushing air in, the other taking the spent hot air out.

Then you only have the smell problem, and you will prolly need to 'scrub' the air using a carbon scrubber and hook it up between inside the tent (as high up as possible, and then hook your exhaust fan up to that. Then any dirty hot air leaving the tent will be scrubbed before leaving your house.
Another cheaper possibility is buying a jar of deodorizer such as ona gel.

SN

[cypher420]

ok bit of a tweak happened. Here are the new materials being used. pretty much same as old lol.

switched out the other fan and got a combo:

1 x 6" Carbon Filter
1 x 6" Inline Fan (340cfm)
1 x 6" x 30 Feet Aluminum Duct Tubing

also different reflector. was cheaper and gave me 2 extra bulbs and little accessories.

I believe the tent comes with a bottom hole and obviously top holes cause i can see them in the pic heh but how do you block the light from entering if you leave the holes open? I'll definitely get a desk fan to help cool and strengthen plants.

if i did need a 2nd inline fan for exhaust would a 4' do? i found a 4 Inch Inline Exhaust Fan Blower 210cfm (last pic) for $80

appreciate the help :pimp:

[bigsby]

A second fan? Dude, how big is that tent? You are in danger of sucking the plants out of there with the size of the fan you are starting with! I doubt you will need another one. Check the links in my signature for a fan sizing tutorial.

[cypher420]

A second fan? Dude, how big is that tent? You are in danger of sucking the plants out of there with the size of the fan you are starting with! I doubt you will need another one. Check the links in my signature for a fan sizing tutorial.

the tent is 4x4x6.5. since i'm only doing 3 plants a time i wanted a smaller tent but it was all they had. if i just need the one fan than thats awsome! less i gotta spend :D

how exactly do you set up the carbon filter? does it hang at the top inside the tent and connect from the left 6" hole of the tent to ducting which connects to the air hood then more ducting and to the right side where the fan will be? so basically everything going straight across then just a flap open at the bottem for air intake?

[bigsby]

That fan will be more than sufficient. You will need a fan speed controller otherwise it will sound like an airplane testing hanger. Dialing down the speed to just want is needed will also add life to your carbon filter.

Concerning configuration, I'm going to point you to this thread where it is being discussed in parallel. (http://boards.cannabis.com/indoor-growing/186396-indoor-grow-box-set-up.html#post2113980) Same exact issues. As you will see in this thread, the guy is going with a vertical hanging cool tube. Seems you could also go this route. Yields are significantly better. Have a look. You will get the answers to most of your questions. After you give that a read post your questions here so that you don't thread jack or at least pose you questions in a way that is relevant to his setup if you post in his thread.

Also, fan sizing is easy. There is a formula that you can plug in. Just look at the fan sizing sticky in my signature below.

[cypher420]

do you mean the "Fans - Not Just Blowing Hot Air!"? I gave that a read, little confusing but the got it for the most part hehe. So how do I know what speed to set the 340cfm inline fan? If theres ducting and obstructions do I just guess? So without changing fan speed it would just stay at full strength and that would be too much?

I drew a setup of what I imagine it to be like. The other thread talked a bit about vertical growing, but i think with my reflector its best to stay horizantal.

they were also talking about "flanges". I had no idea what those were lol i looked it up and seems there just like washers or something. do i need those or can i just duct tape everything to the ducting?

[SpaceNeedle]

do you mean the "Fans - Not Just Blowing Hot Air!"? I gave that a read, little confusing but the got it for the most part hehe. So how do I know what speed to set the 340cfm inline fan? If theres ducting and obstructions do I just guess? So without changing fan speed it would just stay at full strength and that would be too much?

I drew a setup of what I imagine it to be like. The other thread talked a bit about vertical growing, but i think with my reflector its best to stay horizantal.

they were also talking about "flanges". I had no idea what those were lol i looked it up and seems there just like washers or something. do i need those or can i just duct tape everything to the ducting?

According to your drawing, you have only one fan blowing outside air through the light, and then thru the scrubber and out. That's not correct, the scrubber has to be where your fan draws the air from. You have the fan drawing from the outside. You can if you want (its not as good, but works) have your fan pick up air inside the tent thru the scrubber, then continue the air flow thru the lights and out. What that would do is pick up the warm stinky air inside the tent, clean it, and then push the 'warm' cleaned air thru the light and then out. Its not as efficient, because taking cold air thru the lights obviously would keep the temps down better....but I have run up to 5 lights that way in the past. It will work, but not quite as well as a dedicated fan just blowing the fresh air thru the light.
I've worked in the HVAC industry for about 10 yrs, and can tell you that a 6" passive air inlet is not enough for incoming air without forcing it thru using a fan. It should be at least twice that size. What you need to think about is removing the warm air and replacing it with fresh cold air. In order for that to happen, the best way is to exhaust the hot stinky air OUT of the tent thru the scrubber, so your neighbors don't smell it. Of course the air would be replaced with air coming from your passive air inlet.

[cypher420]

so if i just moved the scrubber to beside the fan would that work? but keep the ducting from the left 6' hole of tent to the air hood so cold air still hits it?

I guess i can cut it bigger than 6" or something, btw what do most people use to cover their vent holes during dark periods?


someone else thought a 340cfm inline fan would be all i would need to exhaust the tent. were they wrong or it can still work if i hook it up correctly? lol

[cypher420]

example picture but i'll cut a larger intake hole at the bottom :)

[bigsby]

so if i just moved the scrubber to beside the fan would that work? but keep the ducting from the left 6' hole of tent to the air hood so cold air still hits it?

I guess i can cut it bigger than 6" or something, btw what do most people use to cover their vent holes during dark periods?

someone else thought a 340cfm inline fan would be all i would need to exhaust the tent. were they wrong or it can still work if i hook it up correctly? lol

Dude. Read the sticky. You want to pull the air through the scrubber. Your setup looks like this: Air in Tent > Carbon Filter > Light > Fan > Exit. You can also swap the light and the fan such that you are pushing air past the light.

No need to cut bigger holes. There will be multiple vent holes in that tent. As for light leak from the vent holes, You will place a 90 degree duct elbow outside of the tent. This will prevent light entering from the vent holes.

Let's do the math on your CFM needs.

1. H x L x W / 5 where 5 equals the number of minutes it takes to exhaust all air from the tent.

2. Take that number and add 10% for each foot of duct, carbons scrubber and fan.

3. Take the original number from item 1 and x by 1.5 for each 90 degree duct elbow.

4. Take the original number from item 1 and x by 1.3 to account for the resistance created by the scrubber.

Add up items 1 through 4. This is the CFM of the fan you will need although you should add 15% to account for cooling needs and another 10% for good measure. Get a fan speed controller so you can dial it down.

Let me know what number you come up with. I'm curious.

[cypher420]

just got my light (without hood) and tent today. set it up. looks great, light gets DAMN HOT wow. after 1 min on i was getting sweaty in there. Anyways i'm waiting on my fan, ducting and scrubber in the mail, should be arriving this week. For now i just have the tent doors open and a desk fan blowing the hot air out. the plants are still small so the smell won't get bad till a few weeks after i start flowering i'm guessing.

ok so does this look more right? hehe mounting the scrubber on the top, connecting duct to light hood, then duct to fan and out the tent.

can't do the math since i dont have the ducting, fan and scrubber yet. but heres a guess heh

1. tent size 4x4x6.5 = 104/5 = 20.8 (round to 21 to be safe) 21.
2. guessing i would need about 6 feet of ducting, and lets say the fan and scrubber are 3 feet in total, again being safe lets round to 10 :) so 10% of 21 = 2.1 * 10 = 21 + 21 = 42
3. guessing 3 would be needed. now is it 21x1.5x3=94.5? or 21x1.5=31.5x1.5=47.25x1.5=70.875?
4. 21x1.3= 27.3

21+42+94.5(being safe heh)+27.3= 185 x1.15 x 1.1 = 234 (approx)

heh so might want to check my math on that

[cypher420]

also when you do 12 off is it just the lights you turn off or can you turn the fans off too since there won't be the heat from the light?

[bigsby]

3. It is 21x1.5x3=94.5

Not the other number.

So your fan is going to rock in there. If you haven't purchased the fan you you could easily step down to a smaller fan. Or get the larger fan if you think you may expand in the future. Either way you definitely want a fan controller. Just note, some fans are quite loud. Smaller fans make less noise. Do more research if this is going to be an issue for you. I can recommend some quiet fans if needed.

You can turn fans off with lights out so long as odor is not a major issue. They will start to stink up the place by the time lights come back on. You can experiment. Also, odor becomes an issue once you hit flower although some strains start to smell in veg.

[cypher420]

dang i already ordered that 3 piece set of 340cfm fan, carbon scrubber and ducting. Are fan controllers cheap? guessing you can't use a computer fan controller? when i look it up it mostly gives me those.

I hope noise won't be a problem I never really thought about that part. Its going to be in an open area as well so the noise will travel......i'll have to test it out when it arrives (hopefully this week) and see how it works.


I started my flower phase since my plants have been vegging for 7 weeks now. Since I don't' have any fans (accept for the rotating desk fan) I have the grow light on with the doors open and the fan directing the air out the door. Even with the doors open it still gets really hot in there! Hope this is an ok solution until my inline fan arrives.

at night i just shut everything off, open up 2 flaps and close up the tent.

[bigsby]

What kinds / make of fan?

The good news about an oversized fan is when you dial it down it will make considerably less noise.

Fan controllers can be had for $20 - $30. Search any online grow store for examples. You can probably get them at a local electronic supply shop.

What are the temps and humidity levels? How close is your light to the plants?

[cypher420]

hehe i dont' have a temp or humidity thermostat guess i should order those too. but with the doors open its not that hot. Plus there is a vent right above the opening of the door and its blowing cool air.

so all i could find are dial fan controllers. pics of them below. The lights are pretty far away right now. didn't wanna risk burning without proper vent. from the top for the plants to the bulb their at 34" right now just using the wing reflector it came with. It doesn't say the brand name that the fan is. It came from the company illumaLights i got a picture of it close up.

now i know you hang the carbon scrubber in the tent do you hang the fan inside as well, or mount it outside? I assume just using adjustable straps or something?

[bigsby]

Yeah you want to keep an eye on the temps so that they stay in the 75 - 85 range with 80 being ideal. Going below 75 is not a big deal but too far below and growth will slow. You want to keep away from the high temps. They can deal with 90 for a bit they will suffer over time. Same goes for humidity. I can't recall the range but I believe you want it in the 35 - 50 percent range. Too high and you risk mold and pests. Either of those fan controllers will work.

Moving are is for more than just temps. You want fresh air for the plants all the time. Also, you will want a fan blowing across the tops of your plants. It causes micro stress to the stalks which strengthen over time. You will want that strength later on once the buds start to get heavy.

What is the wattage on that light? You said it was a cooltube yes? I still think you should hang it vertically. You will achieve much better results.

[cypher420]

its a 400w hps. right now i'm just using a Wing Reflector but I will be getting the reflector in the picture probably by the end of the week.


vertical, is that something a first timer should try? heh

[bigsby]

Why not? The guy from the other tread is a first timer as well. It is just a question of setup configuration. Everything else is the same. You should have another look at his thread. You will achieve significantly more yield because the use of light is so much more efficient. You get 360 degrees of useful light. Overhead reflectors are wildly inefficient. In fact, many people don't use them as they reflect heat better than light.

The question I have is can you remove the reflector from that cooltube you ordered. Usually you can but sometimes the reflector forms the back half of the cooltube making it impossible to remove.

Just an aside, you understand the importance of keeping your bulb clean, yes? Before putting it into the socket clean the bulb well removing any / all finger prints. If you install the bulb with finger prints the oily buildup on the bulb creates hot spots on the glass which can decrease the life of the bulb and even lead to failure of the glass. You likely know this but just wanted to add it FYI.