Détails de l'annonce
The sand in your filter should be chemically cleaned at least once a season; either in the fall right before you close it, or in the spring right after you open it. Backwashing will remove any debris the filter traps but oils and lotions will remain on the sand and can eat up your pools chlorine residual.
This will increase your chlorine usage, costing you money, and will also increase the chance of your pool turning cloudy or green due to a lack of sanitizer. The sand should also be completely changed every 5-7 years. Silica sand (the type of sand used in sand filters) starts off having sharp peaks and valleys. It's these peaks and valleys that trap the debris in the filter. As water passes over the sand it starts to round off those peaks. This leads to the sand becoming