Kalkwasser is the German term for limewater, a saturated solution of calcium hydroxide in water. Administering this solution to marine aquariums replenishes calcium and maintains alkalinity, benefiting corals, clams and calcareous algae that build skeletons, shells and crusts from calcium carbonate. Further benefits are that it helps maintain aquarium pH and precipitates phophates. It also reacts with fatty acids and other organic compounds, and this plus the naturally boosted pH enhances protein skimming.

Instructions:

To make kalkwasser: add 2 tsps of calcium supplement mix per gallon of cool freshwater in a closed container and stir. When the undissolved powder settles, the clear liquid above it is a saturated solution of kalkwasser