Concentrated Formula ClearRay® Protection Plus is a concentrated stain and scale preventer that inhibits scale and staining in spas and prevents calcium build up on all spa surfaces. Also clarifies water. Directions for Use: Add approximately 1 oz of this product to the average 400 gal. sp. Add while the water is circulating. Use once each week for proper maintenance and stain and scale prevention. This product should always be added at the time fresh water is add to the spa or whenever the spa is drained an filled. Add other chemicals after this has been used and strictly according to label instructions.