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 Reviewed by cypher420 on 06-19-2010. Can I vent this? 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 Rating: 5

[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 imp:

[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

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. 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