Lighthouse brown sand is specially graded to trap particles in the 20-100 micron range. It is custom ground to high quality specifications to make your sand based filter system run at peak performance. The constant flow of water through a layer of sand removes any impurities in your pool water.
The sand in the pool filter is cleaned regularly through a process called back washing, which allows the sand filter to last between three and five years. After this time period, you must change out the old sand with new sand to resume providing adequate filtering.