Your pool will never have that picture perfect crystal clear look without clean course sand for the water to filter through. It is recommended that your sand in your filter be changed every 2-3 years. However we recommend that hotels and guest houses etc. change there filter sand once a year due to the bather load in pools.
How often should the sand in a swimming pool filter be changed? We recommend changing the sand every 2-3 years. While we have seen filters go 10 years or more without changing the sand and still do the job, they are not as efficient as they should be.
Filter sand has been ground to a size of .45 to .55 mm in diameter and is very rough when new. This roughness is what makes the sand efficient at filtering out the particles of dirt in your water. As this roughness is smoothed out - as stones in a stream wear smooth over time - your filter's efficiency goes down. This means that your system has to run more frequently to accomplish the same task.
This can increase the amount of sanitizer used, thereby increasing your chemical costs!!. In addition we have found that after three years, your sand has worn enough to allow dirt to penetrate so deep that normal back-washing doesn't clean it completely. The result is shorter filter cycles which requires more frequent back-washing.