Ventilation Setup (With Pics)

Alright more question for all you veterans out there. Been contemplating my ventilation system and before I make any expensive mistake I thought Id show yall what I've been scheming.



This is kinda what my idea entails. Im a little shady on the homemade carbon scrubber feel free to pitch in if you tried one
Here is an arial view



Does this system look like it will work? Anything i can situate better?

Now the light Im looking at is 400 watt reflector that houses the ballast. I have my choice of HPS or MH and will only be able to afford one. Would it be better to get a MH then accent with red spectrum CFLs during flowering, or visa versa and use CFls for vegging then use HPS for flowering

I would use cfl for grow and hps for flower..... it looks like a good space, 1 400w hps is good for 1-2 plants in a 4foot by 4 foot space, your room is 2x that size, so get a 600w hps or devide a 4x4 spot in one corner so the light is not to spread out over a large area.... hope this helps with idears

really depends on how big you let your plants get. grow 12 2 ft plants or 3 5 ft plants. its up to you how long to veg them unless your growing autos

Was planning on vegging them for only 6 to 8 weeks. Would that still be in the range on only 2 plants?

Also am I calculating CFM correctly? I was reading someones set up that was similar to mine but his fan was triple the CFM I calculated.
THe method i read was LxWxH / 3 add 20% for carbon filter and 15% for uncooled HID. THat sound right?

Orphen said:

Alright more question for all you veterans out there. Been contemplating my ventilation system and before I make any expensive mistake I thought Id show yall what I've been scheming.

This is kinda what my idea entails. Im a little shady on the homemade carbon scrubber feel free to pitch in if you tried one
Here is an arial view

Does this system look like it will work? Anything i can situate better?

Now the light Im looking at is 400 watt reflector that houses the ballast. I have my choice of HPS or MH and will only be able to afford one. Would it be better to get a MH then accent with red spectrum CFLs during flowering, or visa versa and use CFls for vegging then use HPS for flowering

Click to expand...

Here is my humble opinion (but it's the right thing to do! haha). A 400 watt light will not be sufficient for your 4 x 8 space (many would place 2 x 1000 watts over a 4 x 8 tray). While 2 x 1000 watts is probably too much for your tent, 2 x 400, or 2 x 600 would be a better option. If you want to buy just one light, be sure to get 600 watts or more with a large reflector. Use a reflector that does not contain the ballast. Heat is the enemy and you want to be able to place the ballast outside the immediate grow area You have many more options when shopping reflectors that do not include the ballast. Get a dimmable digital ballast. You can use HPS for the entire plant cycle, or use MH for veg and early flower, and then switch to HPS for final flower. You can dim your ballast and veg with the same light as flower. T5's are a nice cool, efficient, option for vegetative growth if your budget will allow. You may actually be able to save money running T5 lights as they will require less cooling power and they consume less energy than most HID setups. Your tent is 4 x 8 x 6.5, or 208 cubic feet of air space. To properly cool and dehumidify your tent, you should be able to replace the air in your tent 2 - 3+ times per minute; so a fan more on the order of 400+CFM is in order (a 6" Vortex is rated at 450CFM. An even larger fan may be required if ducting or filter is excessive. While using negative pressure is OK, you get much better air exchange if you include an intake fan as well. Use a 4" Vortex type fan for your intake, and a 6" for exhaust. Use a simple thermo/hygro controller to fire your ventilation system as needed. For best results, bring fresh air in from outside through a HEPA rated filter. Exhaust through carbon to filter odors as they leave the tent. Use a separate 4 or 6" fan to 'pull' air through your air cooled lights. Exhausting through your lights does not work well for many reasons; always seal your air-cooled lights and exhaust separately from your room exhaust.

mississippi said:

I would use cfl for grow and hps for flower..... it looks like a good space, 1 400w hps is good for 1-2 plants in a 4foot by 4 foot space, your room is 2x that size, so get a 600w hps or devide a 4x4 spot in one corner so the light is not to spread out over a large area.... hope this helps with idears

Click to expand...

fuuuuuck that shit... unless you mean actual grow floros.

MH works for vegging, nice penetration, especially if your growing taller, more noded out veg plants...


Looks pretty good to me dude but you miiiight want more air pulling over the 400w.... Can you run air through your hood to cool the light? That would be better, put the carbon filter on one side, and the ducting to the inline fan on the other... and draw air through the CF, through the hood & out


Like I have a 176cfm fan, in line with a 250w sealed hood, and a carbon filter on the other side.. my temps in the tent run about 78 with room temp at 71. Again same fan your going to use to vent a 400w space


Or maybe I'm missing something

my .02 i'm not super experienced with managing 400w I just know I have the same fan you have, and nearly half the wattage, and running pretty warm.


note; i'm really ripped sorry if something doesn't make snese

Lol nah, it makes perfect sense man. Obviously the page i have saved of Ventilation is a little off. The formula they gave me is LxWxH / 3 SO i sorta rounded up to 8x6x8 = 384/3
would give me 128. It then has me add 20% for carbon filter and 15% for uncooled HID, which if i did my math correctly it be 172. Quite possibly I fucked up the math (percentages... blehh ) but i think the source i'm referring to is unreliable. I am looking at a different lighting rig now though. Its a big boy kit and would definately require much more ventilation. It is a hood that comes with a six inch cooling fan both HPS and MH and the 1000watt ballast is not built in. All for a rather good price. Im also looking at a 450CFM 6' in Inline Hydroponics Exhaust. I hear these fans are loud as hell though. I definitely don't think I'll have the dough for a muffler. My budget has already increased like 5 times. You think 450 cfm would be enough for 1000watt? Is there a reliable formula out there for this? I've already come across several.