New spiral cover system which aids the operations of opening and closing. The air purge is built into the cover which can be efficient to release the air from the filter. The distance between the upper part of the sand layer and the diffuser head (''freeboard'') has been increased to ensure greater distribution of water in the filtration phase and avoid sand being spilt into he drain during backwash.

Commercial sand filter is used in larger size installations, such as commercial and communal swimming pool, aquatic park, aquariums and water treatment.