Product information

This product is used to raise the calcium hardness in pool water. Low calcium hardness may cause pool water to be corrosive which may result in staining, etching or distorting of all types of pool surfaces. Surface etching by low calcium hardness will become more abrasive and uncomfortable for bathers. Rough surfaces also increase problems with algae and makes cleaning more difficult.


  • For Pool, spas and hot tubs
  • Raises calcium hardness level
  • Helps prevent etching and staining
  • 100% active


  • Multi-use product


Safety Data Sheet (SDS)


Directions for use

Ideal bathing conditions exist at a slightly alkaline pH level of 7.2--7.6, with alkalinity of 80/150 mg/l. This range will also allow the most effective use of other swimming pool chemicals. Determine the calcium hardness of your pool water using Poolcheck 6 in 1 Test Kit (Product no. 767020). Use Pool and Spa Hardness Increaser at the rate of 100 g per 10m3 to raise calcium hardness by 10 mg/l. Dissolve the required amount of Pool and Spa Hardness Increaser in a clean container with clean water and pour slowly around the perimeter of your pool and spa. Ensure both the pump and filter are running to circulate the product effectively. Re test and make any further additions as required.