Why would it be hard to find the ideal co2 level if the light intensity were very low?

sand 60

clay 10

silt 30

sandy loam should be dominated by the sand. as the amount of sand increased, the amount of slit needed to anchor the plants' roots to the sand will also be increased. even though the amount is very little, 10% part of clay is still necessary for proper oxidation.

multiply it by 5 in order for you to understand i cant give an exact answer.