Until recently, the most common solution for problem iron and H2S water involved the use of harsh chemicals & complicated equipment requiring regular care and service by the homeowner or water treatment professional. The A1 Dual Filtration System now offers the “natural” solution for removing iron and H2S. The A1 Dual Filtration System has a proven, patented technology that uses nature’s own oxidation process to eliminate iron and H2S without chemicals, air compressors, areators, and external venturis. It simply uses nature’s own oxidation process.