A sand filter in your pool or Jacuzzi is an efficient way to keep your water clean and clear. They are most effective with clean sand, operating about 12 hours a day so that the entire pool volume is recycled every 24 hours. When the sand becomes too dirty, gets calcified or is saturated after a long period of time, it must be changed. Generally, a filter's sand should be changed at least once every three or four years.
Turn the filter off by switching the main dial to the "Closed" or "Test" position, ensuring that water will not be pumped into the filter system from the pool while you are changing the sand.
Unplug the filter drain to allow all the water currently in the filter system to flow out of the system's pipes.
Disconnect the dial valve at the tank flange and remove the water diverter that directs water into the filtration system after it is removed from the pool. Extract the basket assembly that conducts the housing for preliminary filtering to gain access to the sand filtration elements.
Vacuum the sand out of the filter with the wet/dry vacuum. Vacuum gently to avoid damaging more-delicate filtration components.
Cover the stem drain so that newly added sand will not fall into the stem pipes, where it might contaminate the pool.
Add new sand up to the level indicated in the filter container.
Uncover the stem drain and replace the basket assembly, water diverter and dial valve. Finally, turn the pump back on to re-engage the filtration system.