Intake and output clarification

I have read that the ratio of required intake to out put is 2:1. But before I start ccutting more holes in my precious "window box" I am asking for some more experienced clarification and advice.

I have built the connoisseur's grow box with three copmartments. The veg/mother compartment with 2 x 2" intakes.. a third that bypasses the veg compartment to the flowering compartment; another 2" intake from the veg to the flower compartments; a 3 " conduit from the light fixture to another compartment housing the ballast and squirrel cage fan and a 4" output to a 6"x 10" home made carbon filter.

I am already fairly positive that increasing the diameter for the 3" conduit in my flower chamber will correct my heat issues ( i am running at 104F with the filter on and 94F with it off). But since there is no need to re-invent the wheel as it were, I was hoping for someone to be able to give some rule of thumb or experience to help me with my next step so I don't create another problem along the way.

WOW! Don't all speak up at once! I didn't think it was a stupid question.

Spazmoog said:

WOW! Don't all speak up at once! I didn't think it was a stupid question.

Click to expand...

It was a good question. I think some people might be a little perplexed though; maybe a little intimidated too.

When you say the ratio for exhaust to intake is 2:1, do you mean Cubic Feet per Minute (CFM) in/out, or do you mean size of the diameter in/out?

I am also confused; and i'm glad you put this thread up. If we could get some clarification; that would be great.

I've never heard of such a ratio, I always learnt to have a fan capable of exhausting the volume of the room 2-3 times a minute, and have a passive intake slightly larger than the size of the fan so the air mixes better. https://www.rollitup.org/view.php?pg=faq&cmd=article&id=229
Please don't get pissy if noone answers your question right away, I know this is an electronic age of instant gratification but the human element can still be slow.
Besides which, in the 40 mins between your posts you could have easily found the answer yourself, took me 30 seconds.

Try a month and 40 minutes between posts.

And I am quite aware of how to find answers on the interweb. But you also know that you have to use the right tags when searching. I'm glad it was easy for you. Thats why we ask for help. Because we are having trouble and there are more experienced people out there that know the answer or saw it somewhere along the way.

I have read about "exchanging the air in a room once every 3 min" but how does one measure that?

My question is - is there a ratio to the size of the input (mine is passive at this point) to the output in any given compartment (I have three). My configuration is as follows:
- ~6 cu ft veg chamber with 4" of input
- ~12 cu ft flower with 4" of input
-both chambers are in succession.. veg first.. then flower
- then 6" input to the squirrel fan that moves 236 cu ft in whatever time they usually measure it.

I am only asking because I don't want to start cutting more holes if there is a better way or something I still am not getting. It's easier to not cut the hole in the first place than to repair a hole after I screw up.

Thanks for your help. Please, no more schooling on the best practices of internet searches.

Thanks for the link Hairy Bob... that was pretty much what I was looking for... and I have not been able to find it in such plain english in all my searching.

Still, if anyone has a thought process or formula they use to make no mistake, I would love to hear it. And I am sure all the nubes would apreciate it..... if they can figure out this internet thingy! LOL!

I'm very sorry about that previous comment, I didn't even look at the date, just the time. I'm so used to seeing threads posted by impatient folk who wait a few minutes before haranguing the forum for not giving them attention. I feel quite foolish now.
The FAQ is a fantastic resource, and if every new member read the majority of it before they posted, there would be a hell of a lot less repeated posts on here.
In answer to your question, if I am understanding you correctly your vents run in series, so outside>veg room>flower room>fan>outside right?
So you want the intakes to be slightly larger than the exhaust, as you essentially only have one intake, and one way between the rooms. So all your vents and ducting should be around six inches. Tbh I don't think it matters too much if the intake is slightly larger or smaller than the exhaust, as long as they are roughly the same.

That was just the confirmation I needed H.B.
Thanks for your help! and I do feel stupid about the FAQ thing.... I guess everyone thinks their problem is special and I am not exempt. But it is really nice to hear from someone who has climbed over the mountain and can tell us new guys whats on the other side!

Have a great weekend! I hope everyones 'chores' don't keep them inside!