Aqua Cal 7kgAqua Cal is a premium calcium hardness increaser designed to balance water chemistry in hot tubs and spas. This 7kg container raises calcium levels to prevent corrosion of equipment and plumbing while protecting acrylic surfaces from etching. Ideal for soft water conditions, it dissolves quickly and works seamlessly with other spa chemicals. Maintain optimal water balance for crystal clear, comfortable soaking water and extended equipment longevity.