CO2
The injection of CO2 is an essential part of a successful planted aquarium. It is an integral part of the equation of photosynthesis and can also aid in the chemistry of the aquarium by changing its Ph. CO2 can be added using different methods but only one is considered to be the most efficient and sufficient to keep both plants and fish healthy, the pressurized CO2 injection. Before continuing it is worth mentioning that the water in the aquarium should have a hardness of approximately 4-6 kH so as to act as a buffer to prevent sudden Ph fluctuations when CO2 is injected. A CO2 of around 30ppm (part per million) is the desirable level. The chart bellow illustrates CO2 levels according to kH and Ph:
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\ pH | 6.0 6.2 6.4 6.6 6.8 7.0 7.2 7.4 8.0
KH\ |
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0.5 | 15 9.3 5.9 3.7 2.4 1.5 0.9 0.6 0.2
1.0 | 30 19 12 7 5 3 1.9 1.2 0.3
1.5 | 44 28 18 11 7 4 2.8 1.8 0.4
2.0 | 59 37 24 15 9 6 4 2.4 0.6
2.5 | 73 46 30 19 12 7 5 3 0.7
3.0 | 87 56 35 22 14 9 6 4 0.9
3.5 | 103 65 41 26 16 10 7 4 1.0
4.0 | 118 75 47 30 19 12 6 5 1.2
5.0 | 147 93 59 37 23 15 9 6 1.5
6.0 | 177 112 71 45 28 18 11 7 1.8
8.0 | 240 149 94 59 37 24 15 9 2.4
10 | 300 186 118 74 47 30 19 12 3
15 | 440 280 176 111 70 44 28 18 4
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You can also measure CO2 levels with indication solutions that turn green when the levels are optimum and change color when they are below or above optimum.
