Sand filter: made by fibric glass with flange unions..

sand filter: 

  1:Drain: by-pass filter, the water drained away directly.

  2:Filter: for normal filtering and regular vacuuming

  3:Backwash:for cleaning filter sand bed of accumulated debris.

  4:Rinse:used after backwash to flush valve.

  5:Whirlpool:circulating water to pool by-passes filter.

  6:Closed: shut off all flow to filter and pool