Red Sea NanoMat Replacement Roll (2-Pack)Replacement fleece rolls for the NanoMat Fleece Roller Filter. Although specific lifespan will vary according to system parameters such as volume, bio load, feeding schedule, and initial water quality; each 105' roll of filter fleece should last roughly 4 weeks on a moderately stocked reef system. Bare bottom tanks will typically exhaust rolls at a faster rate. Additionally, usage rate may be significantly higher for the first few weeks after