Increases hardness of pond water.

Maintaining a general hardness of water of at least 7 degress of hardness helps to keep the biological processes working properly thus avoiding stagnation and acidification. The calcium and magnesium forming the general hardness of water are essential for the proper growth of plants and aquatic micro-organisms which consume unicellular algae and help to keep the water clear. 1 Litre treats (1500 Gallons).