Estimating co2 needs

Indoor Growing
#1

CO2
W x L x H x (Desired CO2 ppm - 400ppm) 400ppm average CO2 levels
(1,000 ppm = .001)
(1,400 ppm = .0014)
Example:
Room = 12x12x8
1,152 cubic feet
1,152 x .001 = 1.152
It will take 1.152 cubic feet of gas to raise levels to 1000 ppm. Add 400ppm (avg co2 levels) for a total of 1400ppm.

Set the CO2 regulator to 5 SCFH which = .08 ft3 per min
Divide ft3 needed by flow rate (.08)
1.152/.08 = 14.4
CO2 will be on for 14.4 min to bring total CO2 levels to 1,400 ppm.

1 lbs of liquid CO2 = 8.741 ft3 of gas
20lbs = 175 ft3
5lbs = 44 ft3

100% air exchange every 2 hours ( through cracks, doors, etc. assuming not perfectly sealed.)
1.152 every 2 hours over 12 hour period
(1.152/2) x 12 = 6.912
6.912 ft3 of CO2 needed daily

175/6.912 = 25.32 a 20lb tank will last approximately 25 days In this room.

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Does anyone else use a custom co2 generator?
#2

The numbers are good but in my experience and practice the gas will last much longer if you measure what is really happening. And then make adjustments A two and a half second blast raises my grow from 450ppm to 2500 ppm, I cannot get much lower in timing or rate of delivery the timers won’t go lower and the primary regulator won’t maintain less, just look at the guages settings in my equipment thread. The regulator is at the minimum possible There are mechanical limits to the operation. I only require one 2.5 second blast every 20 minutes to cover my grow area, in twenty minutes the 2500 ppm will dissipate to 850 ppm. Before the next hit. I am not in what is considered a sealed grow room
I am extremely safety consious, I have O.S.H.A. training in the use, and monitoring of safe Co2 levels. I am one of the few growers actually using Co2 monitoring equipment (a data logging meter records temperature and humidity and time as well as actual level achieved have a look at my equipment thread. You only have to average a universally recognized 1000ppm to be effective and achieve a 25% increase in growth another 500ppm or 1500ppm will gain an equivalent increase over that. Is that mathematically a sound estimate? Sure it is, but it is just an estimate that comes from anecdotal evidence a raw bit of information. All I’m saying is you don’t need as much as you think to get the job done when you add up the variables such as rate of dissipation. You also don’t have to fill 100% of the grow room with Co2 . Nothing over the top of the plants needs Co2. The released gas will sink to the lowest part of the area and then dissipate upwards and outwards in all directions.

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#3

thank you for the additional information.
this is just a place to start for those interested in adding co2 to their garden.
a rough estimate as it were.

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