The 4 lbs Hardness Plus is a high-quality pool chemical designed to raise the calcium hardness in your pool or spa water, ensuring balanced, safe, and comfortable conditions for swimmers. Its granular form makes it easy to apply, quickly adjusting hardness levels to the optimal range. Maintaining proper calcium hardness helps prevent corrosion of pool equipment and surfaces while avoiding scaling and cloudy water. This product is compatible with all types of pools and spas, making it a versatile solution for both residential and commercial settings.