Red, I've read all 19 pages of this thread in hopes of finding a set up like mine will be, no such luck. I'll be building a 6'x6'x6' in a completly shaded basement with ambient outdoor temps and humidity quite high. I have to control temp & humidity,hopefully with a 5000btu window a/c, and a dehumidifier if needed, but can't add co2 because of stealth,this will be a sealed enviroment. I hope I can maintain 300ppm from small leaks and cracks? Planning on running a 600w with a 6" air cooled hood(total 8' long) maybee 6" ellbows on each end to block light,this would be the only restriction on the light vent. Planning fan and scrubber to work GREAT, what ever it takes??? If you're scrubbing the air and returning it in the same space does this create a balanced pressure or a accident waiting to happen? If it won't work,TELL ME! if you think its got a chance I would appreciate your opinons on fan size for lights, and fan and filter combo to make it work!!!
don't expect to not make mistakes. They happen and it's the best and most memorable way to learn.
Luigi4Bud you do have it correct that a 141 cfm fan would exchange air in your tent once a minute, but that is more ventilation than you need. You really only need to exchange the entire volume of air once every 3 to 5 minutes. That means you only need to flow about 50 cfm through the growing area. I would just go a little above that with a filter. If your buying a filter get one rated for around 75 cfm, then get a fan rated around 100+ cfm. The scrubber will slow the fan down and it will probably pull somewhere around 50-75 cfm.
For the light I would get something around 200 cfm or more. You'll only need a 4" fan and ducting for a 400w and 200 cfm should cool it down significantly.
-Phr3
PHR3, The basement is completly vented to the outside, I see this as my biggest problem, to control heat and humidity. Outside temps can reach 100 degs. with 95% humidity in the summer time. I thought I had to use a/c, but if I am exchanging the room air every minute or so The a/c would be useless. I was thinking if I vented the light hood outside the room(in the basement) and pulled (inside the room) air thru the filter with a seperate fan for odor it may pull enough fresh air in to be sucessful. I can't safley bring co2 bottles in and out, or propane, so I thought I could control more of the variables, HEAT,humidity, odor and hope to leak in enough fresh air to make it work!
Your cuft calculation in your spreadsheet for spaces is wrong this should be correctHi guys,
I see there's a backlog of questions. I'll try to answer them but please try to use my charts and tables. I really don't want to custom design everyone's growbox from scratch.
I've made another chart that might be more helpful to getting your basic airflows figured out.
One thing I'd really like to point out is that the ventilation requirements to remove heat from the light is far greater than what's needed for the plants.
Most of the small grow boxes and tents are blasting thier plants with an extremely high volume of air. I believe anymore than 1 ACpM puts undue stress on the plants.
If you can get all the heat out of the box, then the requirments for the scrubber drop way down. A small DIY filter powered by a computer fan is all a growbox grower needs to keep the smell down and give the plants a nice environment.
Sorry guys, I'm not explaining myself very well. I'm trying to run two seperate systems, one to cool the lights with ouside air and vent it staight back the outside. I will have a 5000 btu a/c for cooling, and a dehumidifier. I want to run a fan pulling thru a carbon filter exhausting in the room,for odor control ONLY. If I'm not exchanging my room air, will I get enough co2 in the room to be succesful? I'm thinking a 400cf/m fan for the light, not so sure about the carbon filter and fan sizing?. Sorry about the confusion, I really am trying to do this right, MINUS providing 1500 ppm/ co2.