Can I vent this?

[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