===== dkM =====

"dkM" refers to "deca-Kaltsium-Äquivalent," a unit used in some European countries to measure water hardness. It's part of the metric system used to quantify the concentration of calcium and magnesium salts in water, which contribute to its hardness.

Here's a breakdown:

  * d: deca (10^1)
  * kM: Kalzium-Magnesium (calcium and magnesium)
  * 
So, "dkM" is a unit where 1 dkM represents 10 millimoles of calcium carbonate (CaCO<sub>3</sub>) per liter of water. This is a way to express water hardness in terms of the amount of calcium carbonate equivalent to the total concentration of calcium and magnesium ions in the water.

For context:

1 degree German hardness (°dH) is equivalent to 1 millimole of calcium carbonate per liter, or 0.1 dkM.

Water hardness can be measured in various units like parts per million ([[:snippets:ppm|ppm]]), or [[:snippets:mgL|mg/L]], and "dkM" is one such metric used to describe it.