AAAARRGGHH!!! I DONT UNDERSTAND!

[faithlessxxx]

I've just completed one grow in a 1.2m * 1.8m closet, its 3m high too.
I had to keep the door open, and with just a dinky little fan blowing on them from the doorway, they managed to stay at about 27C all the way, under a 400w HPS.

For this grow, I decided to do things a little better.
I smacked out a 12 cm round exhaust hole at about eye level and a 10cm intake at roughly floor level. I inserted the 12cm flex ducting, pulled it all straight and inserted it into my brand new fan which I've set up with a cooltube around my 250HPS.
This is supposed to be my prototype for my bigger lamp which I want to add in a few weeks, once it too has become a cooltube.

I bought a 100 dollar ductfan, 350m3, which was pretty much the biggest fuuck I could get hold of:

TD 350/125 (125mm/360m3/hour) - Hydroponics UK, Hydroponics Systems & Grow Lights

then I connected it all up, turned it on, and stepped back in anticipation.
33 fuuking Centigrade with the door closed, after 20 mins.
about 29C with the door open.

So this whacking great fan which sounds like a monsoon, and is inserted into a cooltube is doing a much worse job at sucking out heat, than my old 20 dollar fan was at blowing in cool air.
What am I doing wrong?
It's driving me nuts.
Also, I have 7 babies that desperately need to get in there quickly.

Things that are confusing me:

The cooltube glass is cool but the air around it is fairly warm. Since the exhaust tube from the cooltube goes to the exhaust opening in the closet wall, how is other ambient air in the room supposed to exit? Do people have double exhaust holes in two walls opposite or something? One for the cooltube, and one general ambient air exhaust?

The fan seems to blow like crazy, but theres not much sucking going on apparently. Wouldnt it be better to reverse the cooltube, and have the fan stormblowing the air across the bulb, through the cooltube, into the flex ducting and out, rather than trying to suck it out?

The exhaust hole is on the same wall as the intake hole. I know thats not recommended, but I had little choice, though I could perhaps make a hole on the other side, with some difficulty. I would think this does not matter much since I'm leading the exhaust air through ducting.

Any help would be amazingly appreciated, I've been grazing my knuckles banging holes and wracking my bleeding brains for 3 days now.

*Rolls a depressed spliff*

faithlessxxx Reviewed by faithlessxxx on 01-26-2007. AAAARRGGHH!!! I DONT UNDERSTAND! I've just completed one grow in a 1.2m * 1.8m closet, its 3m high too. I had to keep the door open, and with just a dinky little fan blowing on them from the doorway, they managed to stay at about 27C all the way, under a 400w HPS. For this grow, I decided to do things a little better. I smacked out a 12 cm round exhaust hole at about eye level and a 10cm intake at roughly floor level. I inserted the 12cm flex ducting, pulled it all straight and inserted it into my brand new fan which I've Rating: 5

[invision]

do you still have intake going, thats where you may be having issues you may need intake for cooler air, if i stop my intake my temps rise over 90F and with intake on it stays about 80F.

[faithlessxxx]

Hmmm, no, someone said intake wouldnt do much so I turned it off most of the time I've been experimenting, though I haven't noticed much difference.
I'll try it again and see what happens.

[stinkyattic]

Intake low... exhaust high... take advantage of warm air's natural propensity to RIIIIIISE and float away... You want another vent of some sort low down.

[faithlessxxx]

You want another vent of some sort low down

Please tell me more about this...
What height?
Must it be opposite because thats a hassle?
What size?
Does it need an exhaust fan?

[invision]

a simple passive intake is all you need

[babystarbud]

hmm

if your ambient temps are high then you arnt going to be able to cool things down too much with passive cooling, you need to cool the room down somhow, or draw cool air from somwhere..

the only benefit to blowing air through the cool tube ( as opposed to sucking it out) is; its easier on the fan bearings, so your fan will last longer

[faithlessxxx]

Passive cooling means?
The room isn't hot in itself. When I turn the lamp off, the temps settle to normal house temps of about 22C in 10 minutes.

What I dont get is when I blew a crappy little fan over them with the door open the last grow, the thermometer registered around 27c. With a great freaking hi-tech fan and two massive holes in my wall, but no little fan blowing over them, I'm getting around 31C. WITH A SMALLER LAMP!!!

What about chopping off the sides of the reflector?

[faithlessxxx]

To the top.
I really need help guys!!!
Should I make a new hole in the brickwall on the opposite side?
Will that make a worthwhile difference?
What should I do?

[latewood]

hot air rises.
so you exhaust at the top of your cab...

you always need to provide your cab...with fresh cool air and cool air is lower to the ground...So, fresh air intake should be at bottom...exact specs...don't matter. cool in: bottom........hot out: top
Whoever said you wouldn't need a fresh air intake is an idiot, and knows nothing of controlled environment issues.

try that and it should work...You might be better off with just an intake and exhaust and forget the whole cooltube effort...See if that works. Goodluck