CO²   KH/PH Chart

Author: Last updated:

This chart shows the dissolved carbon dioxide value of water based on the measurements of carbonate hardness (KH) and pH, which can be easily measured with a test kit. Bear in mind that these values can fluctuate throughout a 24hour period so any reading is only a guide.

For plant growth the ideal range of CO² is between 10-30ppm, and ideally 20-30ppm. This range is highlighted in green.

pH6.06.26.46.66.87.07.27.47.67.88.0
KH
0.5159.35.93.72.41.50.90.60.40.20.1
1.03018.611.87.44.731.91.20.70.470.3
1.5442817.611.174.42.81.81.10.70.4
2.059372414.89.45.93.72.41.50.90.6
2.573463018.511.87.34.631.91.20.7
3.087563522148.75.63.52.21.40.9
3.510365412616.410.36.54.12.61.61
4.011875473018.711.87.54.731.91.2
5.01479359372314.79.35.93.72.31.5
6.017711271452817.711.27.14.52.81.8
8.02401499459372414.99.45.93.72.3
1030018611874473018.611.87.44.73
1544028017611170442817.611.174.4
205903702401489459372414.89.45.9

Note: ppm is the same as mg/l



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