Aquasalt is 100% pure, certified USP-Grade salt, produced specifically for swimming pool and spa chlorine generators. The evaporated manufacturing process is familiar to most people as table salt or food grade salt. Aquasalt is packaged solely for use in swimming pools and spas with chlorine generators and is not intended for human consumption. Aquasalt should be distributed over the greatest water surface area possible to result in the fastest dissolve rate. Follow the Chlorine Generator Manufacturer guidelines for quantity and frequency of adding salt. Avoid piling the salt on the pool surface and brush as necessary until fully dissolved. 40 pound bag size.