I need help...Cfm and Co2 requirements

Discussion in 'Growing Marijuana Indoors' started by trueweedsmoker, Jul 29, 2017.

  1. Starting a knew grow in a different room. I never been good at this part. My grow room will be 8x10x8 tall. 4 1000 watt lights I would be very appreciative if anyone can tell me the cfm's needed to exhaust the room. I would like to use more than 1 fan. I also have central air and it's in my cool basement.

    Also how much co2 to pump into my room every 30 minutes.
  2. Adding CO2 to a ventilated grow room/tent does little if any good. The exhaust fan sucks it out almost as fast as it's produced. It might help a little to get one of those CO2 bags, and use a very slow exhaust, but that's probably a lot of effort for little return.

    There is no scientifically established value for how many cfm exhaust a tent needs that I'm aware of, just guru opinions. The main reasons for ventilation are to keep the temperature down, and to keep CO2 levels normal.

    A CO2 meter can be used to measure levels outside the room, and then the lowest possible ventilation can be used that will keep the CO2 level inside the tent equal to or greater than this. I've done that, and discovered that even a very low flow rate (and fan speed) keeps CO2 levels the same inside and outside. This disregards any temperature considerations.

    Because of your breath, and the basement furnace/water heater, the CO2 levels there are probably already high, especially for city dwellers that get a little free co2 from cars. Normal atmospheric CO2 levels are around 400 ppm, but 500-700 in my basement, according to my CO2 meter.
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  3. That's the setup we use for our flower rooms. But heat is a huge issue and we run 2 (410 cfm) in-line fans to pull heat off the lights and a 10,000 BTU window unit just to control the heat. With that much wattage, the heat is HUGE....but you flower out tremendous plants. LOL We intake air from inside the room and exhaust to outside. As far as CO2, depends on what kind of fresh air you get coming into the space. If you cut off fresh air coming into the room, you'll have to set up CO2. Because of the window unit, we just supplement CO2 with a bottle but the fresh air coming through it is enough. Temp is huge so make sure you can control the heat from those lights before you put plants in there. We tried a 5000 BTU unit but it just couldn't do the job with those 4 large lights. Have you looked at the new CMh lights (at least I think that's the right name for them) that are on the market now? My grow store guy is using them and he says they out perform the LEDs at about 1/4 the price. He says they don't get as hot as HPS or MH on their own and contain all the reds and violets you miss out on with the HPS lamps. We've run HPS for years, but I'm seriously thinking about converting over after talking with him. He said you get better production out of a lesser wattage lamp because of having all the colors spectrum-wise. Just something you might want to check into. TWW
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  4. thank you...I wish you had a journal that I can see. I have a 10,000 btu ac also. I want to exhaust heat from the lights when c02 is off, so I might have it turned on by the hour
  5. Thanks a heap. I plan on exhausting heat when c02 is off so I might have to run it every hour..what would you do?
  6. Sweet...how much did you yield with 4 thousand watts and your ventilation. ..what mutes did u use?
  7. You shouldn't run 2 fans in the same environment if you are drawing passive intake. The fans can work against one another. I run phantom 315 CMH. They're amazing. My LED heats the overall environment more and plants don't get half the PAR.
  8. If your exhaust is shut off at all, for any amount of time whatsoever while running 4 K's you're gonna end up cooking your plants.

  9. She doesn't grow. Never posted pics. Never done a journal. She just blows smoke uo everyone ass and has no idea what's she's talking about. Don't listen to her.

  10. Thanks everyone. So the question is how should I run my c02..Alien 51 who r u saying has never did a grow.. Me or White widow
  11. I really need the help on running it..I need to run it..I did once with 2600 watts and my temps hit 95 but a good 3 p yield. Im running inline fans on the lights. With a good seal it shouldn't effect my c02 right or will it
  12. I don't think she has ever once posted a single picture on GC - so don't hold your breath lol

  13. How could it not affect Co2 if you're venting the area?

  14. Widow White
  15. If it's in a basement don't worry about co2 unless you live alone and are not home very much. Your basement should be full of co2 with a family & pets upstairs.
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  16. Her pics must be behind your shed...
  17. beat me to it!
    Co2 doesn't do much of anything if you have good air movement and ventilation. Its pretty much a wasted practice with the air being exchanged properly. There are some journals on here with people running co2 at night time, without fans on. But I don't know if that actually does anything either. It would be an interesting experiment anyways to do a side by side to see. Generally you always want that air flowing though, depending on how many plants you have in your room. Because if its not moving you can end up with mold and other nasty issues.
  18. Thnx guys. C02 does no good at night. I wasn't gonna run my room exhaust fans during injection just my duct fans from my light

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