Skimz Monzter BR157DC biopellet reactor sets up in minutes and easy to use internal or hang-on biopellet reactor. Biopellets can help remove nitrates by the use of a bacteria that will colonize on the biopellets. The bottom feed with the conical design makes the reactor super efficient, requiring less flow than other designs to fluidize the pellets. BRS suggests 1 cup or 236 mL of biopellets per 50 gallons of total system water volume.