Calcium

Calcium is required by all living creatures.

Under natural conditions, rocks wear down and calcium is dissolved into the water, but this process is slow! Acid rain, deforestation and climate change cause lakes to lose vital calcium and some lakes have fallen below healthy thresholds (especially on the Precambrian Shield in Canada). This has meant that they have lost dominant plankton species.

What it means

Each body of water has its own normal calcium level based on its bedrock. Find out what your 'normal' levels are by testing! 1ppm = 1 part per million or 1 mg/L.

• Calcium levels below 10ppm mean your water is soft! Your pH is more easily influenced by things like acid rain
• Natural calcium levels above 40ppm mean invasive species like zebra mussels can reproduce
• Declining calcium levels and climate change can also lead to low oxygen levels in the deeper parts of lakes