Ventilation Duct Fan For COOLTUBE Question

Hmmm. Then maybe I could use the smaller fan for a cooltube for my 250HPS...
I want to use both preferably and have 650W HPS for flowering.

just for comparison i will tell you what happened to temps in my space when i went from a nonaircooled hood to a 80cfm cooltube then to a 465cfm cooltube. my space was 4ft wide by 2ft deep by about 6.5ft tall. i had a 400hps non aircooled hood, for ventillation i had 2 180cfm exhaust fans at the top and at the bottom a 10inch vent hole with a 10 inch box fan sucking air in. temps were between 79-83 with lights on and i could get the bulb to about 16inches above the canopy. i changed the nonaircooled hood to a cooltube with a 4inch, 80cfm duct fan on it and all the same ventillation in the room. the temps never went over 80 and i could keep the bulb 12inches above the canopy. next i changed the 4inch duct fan on the cooltube to a 465cfm squirrell cage fan and also i got rid of 1 of the 180cfm exhaust fans. once i did this final upgrade the temps were always the same as the ambient temps in my home and i assume i could move the bulb even closer but i need it at least 12inches above the canopy so the light can reach both ends of the closet.
that might help you out a bit to get an idea of which ventillation method would work best for you. good luck.

Ok, thanks for that info, very helpful. I've hung the stuff up temporarily with a 250HPS going, don't want to have to re-spackle and paint because something was wrong. Temps after ½ hour with door closed: 22C.
That seems very promising. Now I'm going to see what happens when I stuff 650 watts of HPS in there....Exciting stuff...

Oh screw it. I ended up at 35C immediately. Im returning the fan tomorrow, and getting this instead:

*TD 350/125.
*125 mm.
*50W.
*Decibel 48/39 dB(A).
*Max. air 370 m³/hour.
*Diam. 155 mm.
*Length 290 mm.
*230 V.

Thats more than twice the power.
Might as well do this properly.
.

as i said before you need a pretty powerful fan to run a cooltube properly, the best choice would be a centrifugal fan like a vortex inline and the second best choice would be a squirrellcage fan like the dayton blowers. the standard duct booster fans just aren't powerfull enough to push enough air over the bulb. the fan you just posted the specs for is still only about 215cfm which is less than half as powerful as the 1 i used for my 400hps cooltube. do a search for ecoplus or dayton blowers, you could probably find a 465cfm one for 60-70 dollars american shipped. my philosophy is always to try to get the best equipment possible so that way when your space is set up you can focus your efforts on growing the plants and not finding ways to get the temps down, humidity up, better air circulation, etc. you can learn from my mistakes as well as others here so you don't have to make them yourself. i wish someone would have told me to get a more powerfull fan when i was 1st building my cooltube, it would have saved me alot of time and money.

Thanks for the tips. I bought the bigger fan anyway, my plan is for that to vent the room with a 250w during first weeks of veg (they're still stuck in tiny plastic cups under some flours and not too happy about it). I'm thinking I'll easily keep general house temps with that. The other fan was less than half of this, and when I tried it with the 250HPS for half an hour with the door shut, it only reached 23C.
During that time I'll prepare the 400w with a cooltube, and add that after a few weeks as needed, and especially for flowering.
I'm hoping that will work.
I also plastered, sandpapered and painted the room with a whole new coat of matte white after making those whacking great holes in the wall, and did the hallway at the same time

Heh, this new fan is a pretty hefty toy, though ;) VROOOOOOOOOOOM!!!!!!!

good luck, i hope it all works out as planned, you seem to have done your homework.