Hey, this is my first post, yay!
So i'm desigining my grow room, hopefully Ill begin building this weekend. It is a closet and is apr. 4' x 6'. Initially I had intended to design my ducting as follows:

carbon filter ---> inline fan ---> reflector ---> muffler ---> exhaust.

(intake under door)

After reading a few threads on Co2 i am wondering if I should rethink my strategy. Co2 seemed like such a big expense not to mention another complicated sytem on top of my exhaust, lighting, and hydro. I wondered if the benefit justified the expense and effort. Well, Ive already spent nearly 2 grand so another 2 or 3 hundred isnt gonna break the bank, and if its going to be the difference between an average yield/quality and something great I really should go that route. So I am considering the following:


intake ---> inline fan --->reflecter ---> muffler exhaust.

(seperate exhaust fan hooked up to thermo)
(inline fan and carbon filter sitting on floor as a recirculating unit)
(Co2 Injection system w/tank)


Is it worth the expense? How much effort do i need to put into designing an 'airtight' room? What about cooling? I have a cool tube, but everytime the fan turns its gonna suck out my precious Co2? What are the benefits and drawbacks to this system?

Thanks all!
Cheers?

is it a coolshade light that needs the fan on constantly - or can you turn it off for 20-30 mins?

if it needs to stay on, then you will have to do a mixture of both.

the plants will need some fresh air from somewhere, both to grow and to prevent diseases.

1) go for the second option to cool the light ; intake - fan - light - muff - ex

2) PLUS get another inline fan, hook it up to the filter, and use to cool the room to a point where you can turn the fan off for 30 mins (e.g) and inject the CO2 during this non venting period - or you will just be venting your precious CO2.
carbon filter - vent
you'll be cooking on gas.

I'm using CO2. i went on the cheap, but not a generator. I'm using paintball gun cans, hooked to a solenoid valve through a regulator set up I got at Lowes (its meant to run air tools) controlled by a PLC (had everything but the CO2. A PLC isn't needed, but since I had a few laying around and love to program them.... Plus it will also control the watering, lights and all. Plus I can ajdust over the internet while I'm on the road) It gives a 1 second shot every 1/2 hour (@20 PSI) So far the bottle has lasted about a month. Dick's sporting goods will refill them for $2.50 for 9oz and $4 for 20oz.

I'm in a small closet with a small grow (1 plant) and only a 150W HPS. There isn't that much heat, so no exhaust fan, just one to move the air around.