Tier1 Replacement for Dynamic 03FIL1300, 817-3501, R173431, Pleatco PRB35-IN, Filbur FC-2385, Unicel C-4335 Pool and Spa Filter for Dynamic Series Systems AFFORDABLE REPLACEMENT: Replacement PRB35-IN-3 Spa filter for 35 sq ft Dynamic series systems and any systems that need 5 inch (Outside diameter) by 9 1/4 inch (Length) filters. INCREDIBLY SIMPLE TO USE: Easily replace your old C-4335, Pleatco PRB35-IN, FC 2385 with the Tier1 R173431 EXTREMELY DURABLE: Durable and Washable Pleated fabric that maintains strength even when loaded with sediment, our high flow core is designed to support the filter while providing industry leading flow rates while causing less wear and tear on your pump. POOL AND SPA FILTER CARTRIDGE REPLACEMENT: This Tier1 R173431 can be used in place of your Unicel C-4335 Spa filter. 100% TIER1 NO WORRIES GUARANTEE: We stand behind the quality of filtration and overall performance of our Tier1 filters! Replace your filter when the pressure gauge on your filter tank reaches 8 psi above the pressure recorded when first installed. Turn off the power to your pump and bleed the excess air pressure of the system using the air valve on the filter. Remove any band clamps and/or lids to your filter. Remove the cartridge from the filter canister and dislodge any loose debris Rinse the cartridge thoroughly with clean fresh water and return it to the filter tank. Secure the tank lid and any band clamps.