intake fan and exhaust size help

[johndoh]

my tent is 1.2x1.2x2
i need to know what intake fan size in m3 i need as the hole is 4"
and what size exhaust size in m3 the hole is 5"

am reading posts everywhere and just need the answer without all the bullshit to go with it.
my humidity is bit high and i have a ram dehumidifier in there.

had a look at the Black Orchid Centri-Flo Thermostatic Fan as they have speed control built in.

will i be able to control humidity better with this fan?

[Jay_GY]

my tent is 1.2x1.2x2
i need to know what intake fan size in m3 i need as the hole is 4"
and what size exhaust size in m3 the hole is 5"

am reading posts everywhere and just need the answer without all the bullshit to go with it.
my humidity is bit high and i have a ram dehumidifier in there.

had a look at the Black Orchid Centri-Flo Thermostatic Fan as they have speed control built in.

will i be able to control humidity better with this fan?

I did work mine out can't quite remember the M3 flow rate but You use the same equipment as me mate although my tent is 1 X 1 X 2 and my back orchid fan does not have temp control I've got two 5" passive intakes with a 600 watt HP's I rarely use my dehumidifier and my RH is 50% after watering what's the air quality like going in?

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[MrC]

Search for a grow room cfm calculator, numbers completely fuck me, I don't really understand it all, but I have a 120mm pc fan intake and 4in extractor with controller always on setting 1/5, tent sucks in and smell doesn't escape

[johndoh]

this is what I work out but don't understand the exchange side of it
1.2x1.2x2=2.88m3/hr

The 4” is setup as intake and the 5” as extractor

1x5”rvk 125E2A1 with rhino pro filter extractor
Rated air-flow: 220 m3/hr

Intake fan
Speed 1 = 20w = 130m3/hr 105pa
Speed 2 = 35w = 155m3/hr 125pa

I also have these not in use

1x5”rvk 125E2A1 220 m3/hr
1x4”rvk 100E2A1 175m/3hr

I also have a Ram 10l dehumidifier
Will this controller help to sort my problem out with the humidity?

[MrC]

Can't offer any insight in to technical data etc sorry, but my tent is 1x1x1.8 and I've got an rvk 100L (4in) had it on last grow too. Someone else may explain it better

[Valentina]

I must admit, I am curious: How many times does the air inside the tent need to be exchanged per minute, or hour, for it to be "right"? There used to be a figure floating about but that seems to have disappeared.

Or at least, can't find it in the Ventilation section, and a lot of blurb with no substance on the web.

[tlh2496]

this is what I work out but don't understand the exchange side of it
1.2x1.2x2=2.88m3/hr

The 4” is setup as intake and the 5” as extractor

1x5”rvk 125E2A1 with rhino pro filter extractor
Rated air-flow: 220 m3/hr

Intake fan
Speed 1 = 20w = 130m3/hr 105pa
Speed 2 = 35w = 155m3/hr 125pa

Hi Mate, the 5" A1 won't cut it mate, you lose approx 25% of fans cfm when you add on carbon filter and ducting. Ideally, you'd want the 5" L1 (323m3/h) (323 - 25% = 242.75m3/h) as the A1 is only rated at 220m3/h, add cfilter / ducting then your A1 becomes 165m3/h. You need a minimum 230m3/hour in that size of tent (I run Green Room 1.2 x 1.2 x 2.0 with passive intake and 6" Can Fan Hi-Power One 725m3/h on a variac speed controller at 40%).

Doesn't matter what size intake fan as you need to maintain negative pressure to stop smell escaping, etc so the extraction is the fan that matters.

You should sort out any humidity issues with more airflow so get an L1 then you could use either the 1x4”rvk 100E2A1 175m/3hr or use the 1x5”rvk 125E2A1 220 m3/hr with a speed controller.

[MrC]

Hi Mate, the 5" A1 won't cut it mate, you lose approx 25% of fans cfm when you add on carbon filter and ducting. Ideally, you'd want the 5" L1 (323m3/h) (323 - 25% = 242.75m3/h) as the A1 is only rated at 220m3/h, add cfilter / ducting then your A1 becomes 165m3/h. You need a minimum 230m3/hour in that size of tent (I run Green Room 1.2 x 1.2 x 2.0 with passive intake and 6" Can Fan Hi-Power One 725m3/h on a variac speed controller at 40%).

Doesn't matter what size intake fan as you need to maintain negative pressure to stop smell escaping, etc so the extraction is the fan that matters.

You should sort out any humidity issues with more airflow so get an L1 then you could use either the 1x4”rvk 100E2A1 175m/3hr or use the 1x5”rvk 125E2A1 220 m3/hr with a speed controller.

Good explanation mate, cut it down for the dum dums like me

[johndoh]

and me that's why I posted....lol

[tlh2496]

glad to help out guys. Took me 3 x Tent setups until I got environment dialled in. Still a nightmare in winter If you want the Black Orchid, the BO-CF-125-TEMP-UK Black Orchid as it moves 355m3/h before filter / duct. 266m3/hr after filter / duct added