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Entry Date
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Nick Name
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Location
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Saturday, July 27, 2019
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Matt D.
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Connecticut
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Entry 149 of 210 |
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Why Two Systems?
One is dedicated to enriching the structure with CO2 up to 1050ppm and another to help ensure the levels do not drop below normal atmospheric levels of 400ppm.
Atlas 8 (CO2 Enrichment- Target Level: 1050ppm)
This system that has been the focus up to this point (Atlas 8) and is set to maintain the conditions in the structure at 1050ppm (+/- 50ppm). Based on random checks, this system has been functioning properly. However, this system automatically stops dosing CO2 when the vent fan comes on (which is on a thermostat to come on at 86F+ temperature) to help ensure the CO2 is not simply vented out of the structure.
During the heat of the day the CO2 levels were dropping below the normal atmospheric levels of 400ppm despite continual venting. How is this possible when the outside air contains 400ppm of CO2? My theory is, during times of high light intensity photosynthesis is most active meaning the plant is consuming CO2 in the greatest quantities. Even though outside air is being pulled through the structure is not enough to replenish the rate at which the CO2 is being taken up by the plant. This situation is causing the levels of CO2 to drop below normal atmospheric levels, which can potentially lead to plant stunting. Since my Atlas 8 is off during times of venting I decided to implement another system to correct this daytime CO2 depletion issue.
Atlas 9 (CO2 Supplementation- Target Level 400ppm)
The smaller controller in the lower right of the image (Atlas 9) has a simple but important task of maintain CO2 levels of only 400ppm which is the atmospheric level. This system is not connected to the venting system, but the sensor does have a photocell, so it will only dose during daylight hours. So, even if the Atlas 8 controller is off due to venting this system (Atlas 9) will help ensure the plant never experiences CO2 levels that are below atmospheric levels even if the plant is actively consuming CO2 at a high rate.
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