In these ponds, the SolarBee can correct many of the same water quality problems that occur in facultative ponds and, in addition, in many cases the energy saving will pay for the SolarBee(s) in one to five years. Partial-mix ponds, due to their heavy loading, exert a downward pressure on pH that ultimately leads to unnecessary sludge buildup in the front-end ponds and high nutrient loading in the final pond. After several years of operation, these conditions can cause algae-related BOD and TSS problems, and high ammonia (N) and phosphorus (P) in the effluent. The SolarBee can usually correct all of these problems. For more information, see Enhancing Your Existing Partial-Mix Pond brochure.