Filter sand is replaced every ~3 years (or sooner if it gets very dirty, or if oil gets into the water). There are chemical cleaners for the sand, but to remove all residue, change it.

Step by step

  1. Turn off the pump and set the 6-way valve to "Closed".
  2. Open the filter's top lid and the bottom drain plug to empty the water.
  3. Cover the vertical standpipe (manifold) so no sand gets inside.
  4. Scoop out the sand carefully without damaging the plastic tubes. Wear gloves: sand is abrasive.
  5. Fill the filter halfway with water (cushions the sand and protects the tubes).
  6. Add the amount and grade of sand the manufacturer specifies.
  7. Clean the neck well, uncover the standpipe and close the lid.
  8. Run a backwash and then a rinse before filtering again.

Alternative

Crushed glass replaces silica sand: it's less porous, washes better and lasts longer.