Bands are placed on cartridges to prevent pleats from “fluttering”.  Fluttering is caused by water turbulence and pressure inside the canister of the filter during the filtration cycle.  These bands also help to maintain the pleat spacing which in turn assists the filter cartridge in lasting longer, filtering better and cleaning the cartridge filter much easier.

 2)  The pressure inside a spa or smaller filter is less than that in a larger pool filter thus no band is required.

On a well made cartridge, bands carefully adhere to the outer edges of the pleat fold.  These bands rarely come loose.  However, if a band splits it will not affect the filtration performance of the element and does not affect the warranty. When the bands become loose and worn or breaks off it is generally time to replace the cartridge element. 

Note:  Although soaking a filter element in a mixture of muriatic acid and water is permissible it is NOT recommended due to the corrosive components in acid that will deteriorate the filter media much faster and decrease its lifespan.  This will also deteriorate the glue that holds the bands and cause the bands to fall off prematurely.  For specific instructions see “How Do I Clean My Pool or Spa Cartridge?”