Softener efficiency, capacity, and hardness leakage are all linked. A highly efficient softener will typically produce a lower quality of softened water. Lower quality softened water is adequate for most residential and commercial applications and is important for minimizing the negative environmental impact of softeners. Some applications may require very high quality softened water and efficiency will be sacrificed. The lower efficiency setting can be minimized by a simple staged softening system design. The first softener is set for the highest possible efficiency, a second polishing softener is regenerated infrequently with a high salt setting. The chart below shows typical softening system curves for these three important factors. For most applications, softeners should be set to use 6 pounds or less per cubic foot to ensure highly efficient operation and 10 pounds or more for the lowest hardness leakage.