Sand filters function by moving the water from the top of the tank through the sand to the bottom of the tank via high pressure. As the water trickles down, the sharp edges of the sand grains catch particles like dirt, debris, and body waste materials. Smaller and smaller particles are removed from the water as it cycles through until the sand becomes too dense and needs to be cleaned AKA backwashed.
Backwashing Your Sand Filter
To cleanse the sand, the sand filter will need to be backwashed (manual or automatic). Backwashing your sand filter reverses the flow of water through the sand, starting from the laterals at the bottom and working its way up to top, collecting debris and particles as it goes.
Once it works its way to the top of the filter, it is then sent to waste (meaning it will be disposed of and won't return to the pool). Backwashing can be completed within minutes and isn't a labor or time-intensive process.
After the backwashing cycle is complete and the system has been rinsed, the clean sand can restart the process of filtering the pool water once again.