The table below illustrates teh relationship between pH, Carbon Dioxide (CO2) content and Carbonate Hardness at a temperature of 77 °F (25°C)

°KH	10 mg/l CO2	35 mg/l CO2 Ideal CO2Level	60 mg/l CO2
2	pH 6.8	pH 6.3	pH 6.0
4	pH 7.1	pH 6.6	pH 6.3
6	pH 7.3	pH 6.7	pH 6.5
8	pH 7.4	pH 6.9	pH 6.6
10	pH 7.5	pH 7.0	pH 6.7
15	pH 7.7	pH 7.1	pH 6.9
20	pH 7.8	pH 7.3	pH 7.0