How to Convert a Desjoyaux Pool Into a Sand Filter Pool

Clear an area for installation of your sand filter. In general, the sand filter should not be more than 6 feet above the water level and as close to the pool as practical. Install the sand filter on the ground, on gravel or on concrete as specified by the filter manufacturer. Leave your Desjoyaux pool filter running until your sand filter installation is complete, because you can’t reuse any Desjoyaux parts in a sand filter.

Assemble the sand filter according to the manufacturer’s directions. In general, you install the vertical filter pipe and laterals in the filter vessel, plug the vertical pipe to keep sand out, fill the filter vessel half full with water and pour in the amount of filter sand specified by the manufacturer. Clean any sand off the top of the sand filter. Install the multiposition filter valve onto the filter vessel, connecting it to the filter vessel in the manner specified by the manufacturer.

Connect the sand filter to the circulating pump with PVC pipe and elbows as specified by the pump and/or filter manufacturers. Assemble PVC pipe sections together with PVC primer and cement. Connect the filter valve’s intake port to the discharge port of the pool pump. Connect the filter’s waste port to a PVC pipe or flexible hose for discharge away from the pool.

Assemble the suction line that will withdraw water from the pool for filtering and the return line that will return filtered water back to the pool. Connect the suction line from the pool to the pool pump intake as specified by the manufacturer. Connect the return line into the pool to the sand filter’s return port. When making threaded connections, apply plastic pipe sealant to the threads and tighten hand tight plus one turn.

Connect your sand filter pool circulating pump to a ground-fault protected, 120-volt, 20-amp electric outlet. Install electric service to your sand filter pool pump according to state and local electrical service codes. In general, electrical controls must be at least 5 feet away from the sand filter unit.

Prime the circulating pump if necessary. Set the sand filter’s valve to the “backwash” position. Open the air bleeder on the sand filter and start the circulating pump. Close the bleeder valve when a steady stream of water comes out. Backwash for three minutes. Stop the pump. Move the valve to the “filter” position, open the air bleeder again and start the pump again. Close the bleeder when a steady stream of water comes out. Allow the filter to run. Check for tight connections and correct operation.

Disconnect electric power to the Desjoyaux pool filter at the breaker panel once you have verified correct operation of your new sand filter, and secure the now-unnecessary electric line according to local codes. Remove the filter assembly and circulating pump from their enclosures by unscrewing and unbolting components. Unbolt the Desjoyaux filter housing from the pool wall and pump vault, pull it up and out of the pool. Unbolt the Desjoyaux pump vault from the pool wall, pull it up and fill in the space with soil. Install new pool coping to cover the place where the Desjoyaux filter system was installed.