ventilation issues; HELP

[lray21]

Hey guys, so I have some questions regarding ventilation. I have a 150w hps in a rubbermaid box setup. I have three fans in the chamber, and I am still having a hard time getting the temp down. should i scrap the hps and try cfls? or does someone have any recommendations? I also want to keep this grow as stealthy as possible

lray21 Reviewed by lray21 on 05-05-2010. ventilation issues; HELP Hey guys, so I have some questions regarding ventilation. I have a 150w hps in a rubbermaid box setup. I have three fans in the chamber, and I am still having a hard time getting the temp down. should i scrap the hps and try cfls? or does someone have any recommendations? I also want to keep this grow as stealthy as possible Rating: 5

[headshake]

you need to be exchanging the air in your space at the MINIMUM rate of once every 5 minutes, preferrably every 1-2. without knowing the arrangement of your fans, it's hard to say what specifically you need to do.

fans are rated in CFM, or cubic feet per minute. cubic feet= L x W x H.

keep in mind that you want to be pulling more air out than you are pushing in. you want to create a negative pressure inside your box to get air flowing. if you use a fan for intake and exhaust, you want the fans to move the same amount of air (CFM). keep your exhaust fans up top (heat rises) and your intakes low (cold air stays low).

you might also consider a cool tube. stay away from the CFLs as much as possible as you will be dissapointed in the results (if not now, eventually) and just end up going back to a HID.

welcome to the boards and good growing!


-shake

[lray21]

Thanks shake on the advice. def gonna do some work on my fans.

[bigsby]

See the link in my signature below to the sticky on grow room setup. The second entry deals extensively with fan sizing issues. It will help you work through all of your fan issues. Note that a fan speed controller is good to have. You want to over estimate your needs slightly and then then dial it back to the appropriate setting such that you setup doesn't sound like an aerodynamics test chamber. Size it too small and... well you don't get the air exchange needed. Good luck!

[lray21]

bisby, thanks for the link. I think my main issue has been the intake is larger than the outake. Im gonna open it more. my grow space is like 9 cubic feet tops. so I would think 3 fans would be overkill. we shall see.