What is a major effect of low calcium hardness in pool water?

Low calcium hardness in pool water can lead to significant problems, particularly causing corrosion of pool surfaces and equipment. When the calcium hardness is low, the water becomes aggressive; it leaches minerals from surfaces such as plaster, grout, and metal fixtures. This aggressive nature of low-calcium water can result in etching or pitting of plaster surfaces, as well as deterioration of metal components, fixtures, and plumbing systems. Maintaining balanced calcium hardness is essential to protect the longevity and integrity of the pool structure and equipment, ensuring a safe and enjoyable swimming environment.