Protects Pool from Stain & Scale: Pro Series Stain and Scale helps protect pool surfaces and equipment from the effects of stain and scale buildups caused by: excessive calcium, iron, copper, and other minerals. Helps Reduce Scale Formation: This product does not add phosphates or harsh acids. The Pro Series Stain and Scale helps prevent scale from forming on chlorine generator and UV crystal lens to help them perform at the best rate possible. Compatibility: This product can be used with most sanitizing systems besides biguanides, and is compatible with all pool surfaces. Directions: For initial dose, add 32oz per 10,000 gallons to the pool water evenly around the edges. if water hardness level is above 400 ppm (parts per million), metal readings are above 0.5 ppm, or if being used during start-up of a new plaster pool, wait 24 hours and add a second initial dose. Tested and Proven Effective: Natural Chemistry products are known for delivering reliable results and making water care less complex. Natural Chemistry carries an extensive line of pool and spa solutions that match your unique needs.