Hey there peoples, quick question. I'm pricing carbon filters/fans at the moment but I don't know how much transfer I need. My drobe is 8'x2.5'x6'. So, how many cfm should I be looking for?

Btw, growroomtools doesn't work for me. Nothing for fluorescents in there.

Thanks for the help!

The growroom tools are working,dont forget to press "calculate" at the bottom!

I mean it doesn't apply to me. I'm using fluorescents and all it has is MH, HPS and CFL.

use cfl it shouldnt be far of

In that case use as big and as many as possible,the more the better i say.After all they don't really give off any heat!

Why use fluorescents anyway?,with that kind of space you could get some decent lighting in there as long as you got decent air exchange,if you insist though i would just use the cfl tab as a guide as "Station " above said.

I just ran out of money and fluorescents were the only viable option at the time. The drobe itself was the wallet-smasher.

So I saw that on the tools it calculates for a complete exchange every three minutes. At 120 cubic ft. that means 40cfm sooo, I guess the weakest filter available?

Considering that I'm just thinking about putting some activated carbon sheets over the outtake. Would that do the jorb?

No.They are totally inadequate for filtration purposes,you will need a proper carbon filter can.With the extraction fan i would go for at least a 125mm with that space.It's always best to get a bigger one as you can always slow it down and a small fan has to work harder meaning more noise.

How many watts are you growing with? Floros do produce as much heat at HPS, it's just a different kind of heat....(convected rather than radiant). Taking into account the heat from the lights you probably need more than 3 actual air changes per minute - aim for 1....

Take rated fan capacity's with a big pinch of salt. You get nothing like the rated flow once you add a bit of ducting and a proper filter. You also need a fan that can cope with the pressure drop caused by a proper filter ducting etc...no cheap axial nonsense. For something like an RVK or Ruck assuming a loss of 50% flow rate is not a bad starting point.

I guess you are in the states talking CFM, not sure if the same brands of fans are available over there as we commonly use in the UK.....