Hi Guys and Gal's

Ater reading most of the threads on here recently , i have come up with a design (not totally original , but a bit from a few peoples setup , that i liked the look of , any way here it is . Measurements r 5 1/2 ft H x 2 ft W x 4.ft long

Theres just one thing i need to get clear before i start to build this , i am only planning on using one decent fan for extraction , if you look at the design , it splits the ducting , so it pulls cool air from outside thru the bulb and out thru the carbon filter as well as out fron the growbox ceiling .

After a bit of a ramble , what size of fan would i need to get in order to perfom both functions , or , if i knock out the cool tubes cool air duct , and let it draw direct from the growroom to cool the bulb , would this defeat the point of the tube ?


Any help appreciated

Hopefully Soon

Hi Hopefullysoon

If you start trying to get the fan to pull from 2 different intakes, it will pull more airvia the easiest route, in this case, the air coming from the grow room. This will seriously reduce the amount of air moving across your bulb and through the cool tube. So it is best IMO to....

yeah , thanx chip

i wasnt sure which way to go , but i catch ya drift

2 equal sources of the same air , splits the fan down the middle , thats what i was after , but wondered if doin it that way would have the same effect

thanx

Hopefully Soon

I'd agree with Chip about splitting the flow - nearly impossible to achieve in practice!
Logically the best run would be - filter - fan - light- exit - that way relatively cool air is sucked through the filter - through the fan - then is heated by the bulb - thence to outside. There's several advantages, particularly in keeping the fan cooler - it'll last a lot longer that way! The other thing I've always wondered about using a "cooltube" system is how much light/useful spectrum you lose from the glass.

You need to extract from the highest point of your grow room as that is where the heat is

I use a 6" lti fan ( located in attic directly above grow room) and the ducting is flush with the ceiling, and I use a 12 inch oscilating fan that is tilted back so that it blows at full speed up through the canopy, and then takes all the heat from the lamp out of the open end of my shade and hopefully straight out throught the extractor.

The temp at canopy level never goes higher than 76 c

I used to have the ducting attached to the open end of my shade so that it literaly sucked the heat away from the lamp, but the overal grow room temp was always up in the mid 80's

I don't use a carbon filter either as I'm venting straight outside so that will have negative effect on your air flow.

If I did need to use a filter then I'd maybe consider an 8" extractor instead of the 6" to help compensate for the reduction

Peace
Joolz

Hi again guys

Had a bit of a re-think and come up with a couple of possible options (i think)

The main thing to add here is I dont mind spendin on the kit to sort it , as it pays not to scrimp in the long run , but ideally it's like pc , bare bones will do me to start with , then you upgrade as ya go.

Option A

Option B

option B seems the most practiced method, from wot ive seen within our hallowed walls.

edit just missed some spacing