The importance of pool filter sand.
Granules of sand are irregularly shaped and make an efficient filtering medium, as evidence by the many freshwater creeks that are naturally filtered by sand.
Sand filters contain a deep layer of sand that traps dirt and debris as water flows through it. The trapped particles fill the spaces between granules of sand and actually help the filter collect even smaller particles. Over time, the accumulation of trapped particles will restrict water flow, the pressure inside the filter will increase, and it will be time to backwash, or clean the filter.
When the sand in the filter is clean, water passes through easily. When pool water is unbalanced and the filter isn’t cleaned properly, mud balls can form and impede the filtering process. As the situation worsens, the water forces channels through the sand, allowing unfiltered water to pass back into the pool.
This is why it is important to get your Filter sand change every SECOND year!