Most water supplies contain some naturally occurring fluoride. Fluoride can occur in drinking water naturally as a result of the geological composition of soils and bedrock. Fluoride also enters drinking water in discharge from fertilizer or aluminum factories. The EPA has set the level of protection for fluoride at 4.0 mg/L or 4.0 ppm, to prevent potential health risk.Aries Inline Fluoride Reduction filters utilize the advanced media technology of ResinTech® SIR-900 media, a synthetic aluminum oxide that remove Fluoride by a chemical reaction with the media. ResinTech® SIR-900 has minimal shrinkage /swelling and low-pressure loss, and can be used over a wide pH range. These high capacity cartridges are available with Quick Connect connectors in 6" and 12" lengths. Aries Inline filters cartridges are designed for low-flow, point-of-use filtration.