10" X 54" NSF Certified polyglass tank with base, lifetime warranty. Pentair/Fleck 5600 Control Valve, 5 Year control valve warranty. Calcite media used to balance pH levels to 7 1/8" X 1/16" Coarse gravel.Calcite media is used to neutralize pH levels that are acidic (pH levels less than 7). Calcite is calcium carbonate which automatically self-limits the dissolve and stops at a pH level of 7.10" X 54" pH Neutralizer has a flow rate of 10 gallons per minute (GPM). Additional Details ------------------------------ Product description: 10" X 54" NSF Certified polyglass tank with base, lifetime warranty. Pentair/Fleck 5600 Control Valve, 5 Year control valve warranty. Calcite media used to balance pH levels to 7 1/8" X 1/16" Coarse gravel.Calcite media is used to neutralize pH levels that are acidic (pH levels less than 7). Calcite is calcium carbonate which automatically self-limits the dissolve and stops at a pH level of 7.10" X 54" pH Neutralizer has a flow rate of 10 gallons per minute (GPM).