Up to 12,000 gallons per pair depending on the quality of the influent water. 2.75″ x 2.75″ x 9.75. Filters are comprised of a specialized blend of activated carbon. The BOROUX foundation filters contain silver, an antimicrobial agent, to prevent microorganisms from degrading the product itself. This filter is not intended to filter microorganisms. Fits most gravity-fed water filtration systems and fluoride filters. Scrub the BOROUX foundation filters every 3-6 months. Using an abrasive scouring pad, carefully scrub the surface of the filters for several minutes. DO NOT use soap or detergents on the filters. Re-prime the filters, install, and perform the red dye test to ensure proper installation of the filters. BOROUX foundation filter / Model BX·FND9·2. Two BOROUX foundation filters. Red Dye Test Solution. Based on independent testing for the reduction of chlorine at 6,000 gallons per filter. While testing was performed under standard laboratory conditions, actual performance may vary. The contaminants or other substances removed or reduced by these filters are not necessarily in all users’ water. Filter performance may vary based on local water conditions. 1,1,2,2-tetrachloroethane.