Fans/Aeration/Ventilation

Discussion in 'Growing Marijuana Indoors' started by KalL, Mar 26, 2012.

  1. Hey guys just need a few questions answered.
    First things first. The grow room is 90 square feet/705 cubic feet, will have 4 1000w HPS lights, hooked up with a CO2 generator, complete grow room controller, and true aeroponics.
    Ok, now here comes the questions. I am looking for the best/optimal ways to go about this, not what can just get by.
    1) What size CFM fan should I use to exhaust the new and old air in and out of the grow room?
    2) Does the air literally have to be new & fresh? Does it have to come from outside, or just outside the grow room (aka my house)? Likewise, Can the exhaust be vented into my house as well? Or with the CO2 generator, that may be a bad/unsafe idea?
    3) How many fans or CFM's should I have blowing the stale air around the room until it gets vented out by the exhaust? (Would an average ceiling fan be enough, or is that too gentle? As I have one directly above the grow room).
    4) How often should I exchange new air in for the old out the exhaust?
    Thanks guys, Kal.
     
  2. 3ish minutes @ how often should have be able to completely exhaust room. So 705/3 + resistance from ducting/filter = fan/s size. Might be looking for a 8" or a pair of smaller exhaust fans it looks like


    There's something, only a small part of what you asked tho sorry
     
  3. Aye, a little something is better than nothing :smoke: Thanks bro
     
  4. If your running co2 you only need to exchange air 2-3 times per hour. Air doesn't have to come from outside just outside the grow room. But to cool 4 1000 watt lamps you will probably be best off with 2 fans. ! fan for each pair. 1000 watt lamps need lots of cooling. Also need to think of how your going to run a carbon filter.
     

  5. Completely cycling in new air every 30 min? Do you mean just circulating the air already in there around? I though you only needed to do that a few times a day? Wouldn't that give like no time for the CO2 to be in the room lol?
    I'm fine with getting a fan per light if heats that big of an issue, but I didn't think it would be in such a big room.
    Thanks, Kal
     
  6. All depends on if you got ac. If the only way you have to cool your room is exhausting it then you need to run them more often. But if you can run ac you could seal your room up completely. Since co2 is much heavier than air most of it won't get sucked out, but yes there is some loss to exhaust.
     

  7. Well like I said, I'm looking for OPTIMAL, to make the highest yield/best bud. So if AC will help with that, then I'd get an AC. But do you need to worry about it getting too cold at night? Do you need a heater for that?
    Even if I used AC, how often would I need to change the air?
    Do most of you guys agree with this? ^^^
    Thanks, Kal.
     
  8. I will start this by saying...

    Check out my Blog on here. It is beneath my name
    <--- around here somewhere

    1) I suggest you have two fans. One fan on an enclosed circuit to pull air in from outside, through the lights to cool them, and back outside. This will help keep the heat from the lighting to a minimum while preventing the loss of CO2 and bud smell. The second fan should be dedicated to a carbon filter and run all day every day to remove odor from your "positive pressure" grow room. This prevents the smell from leaking into your apartment. By using a Y-Joint in the ducting, and a flow damper, you can use this fan to exhaust the room when required. I believe these can be automated by a thermostat for a price. Two 6" fans would work fine, but you could use a 4" on the lighting and an 8" on the filter/exhaust if you wanted.
    2) 1500ppm of CO2 isn't dangerous. You can ventilate into your apartment... but that isn't to say there is Zero risk here. You would be wise to just use the outside air when you can. I do vent my heat into the apartment but I don't use CO2.
    3) The ceiling fan will probably only be in the way of the lights you need to hang. The more breeze you can get in there the better. Plants cannot go get air, it has to be passed across the leaf surface, so I would suggest at least four 16" pedestal circulation fans, one in each corner. A box fan on the floor would help also. Air circulation is of vital importance and you would be best served by having too many fans on low than too few fans on high.
    4) As infrequently as possible. Some growers work in a purely enclosed environment, venting only during the night period. Personally, I would vent the room twice during the light schedule, or every 4 hours. 4 hours after lights on, 4 hours after that, then one last time as the lights turn off.


    Aeroponics is a major undertaking. Make sure you have access to plenty of clean water, and the ability to drain off a reservoir if a bad batch of nutrients are present. I think that if you take a look at my blog you might get some ideas on how to set it up.

    The number one investment to controlling this setup, especially because you are using a CO2 burner and not a tank, would be a mini-split AC unit. Although expensive... you could get by on a 20,000btu unit without much issue.

    These sort of grow rooms are quite the adventure. To fill the growing space you're going to need access to a lot of clones, and a lot of water, for an aeroponic SOG. I think that perhaps you are a little ambitious here and you might want to take it one step at a time. Set up a veg tent, then a flowering tent, then add the environment control. I don't know if you're best served by using the entire space as a grow room because I'm not sure what access you have to clones... or what your medical limits are (or if you care about the law).
     
  9. #10 KalL, Mar 27, 2012
    Last edited by a moderator: Mar 27, 2012
    I am not growing over my legal limit. But my legal limit is very high :smoke:. I live with my girl & she can grow as much as me, so we may double the grow size. I have Already dropped G's on this set up. Only things left are the fans and what not, and plumbing for the Aeroponic system (should be easy, have tons of aquarium experience). Just now starting the grow room.
    Thanks for all the advice man.
    ~I will get 4 large fans to move the air around.
    ~What do you think is the optimal times to bring new air in?
    ~Are you saying to run the carbon filter 24/7 for air circulation? Or the exhaust? I'm guessing circulation fans, but doesn't that remove the smell/flavor/quality of the bud? Or no?
    ~From the sounds of that, I think I'd rather be safe than sorry. I'll just have the exhaust go outside.

    Btw, I am using 6" net pots, but I do have 2" ones if you think those are better.
    I really son't care about start up costs. So any suggestions are much needed.
     

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  10. The only thing i'm thinking about if I do double the grow size is: Yield wise would it be better to have 88 sqft @ 6364 lumens/sqft? Or 154 sqft @ 3637 lumens/sqft?
     
  11. I'm just tryin to get an awesome room rollin guys, bump :)
     

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