If you have a sand filter we recommend backwashing once per week or when your pressure is reading above 20PSI. This allows the filter to clean out built up algae and dirt it has collected. It also keeps your water pressure coming out of your jets strong. The standard time to backwash is about 1 minute and then a 30 second rinse. One trick I use is to watch the water coming out of the backwash line. At the start it will be dirty and eventually the water coming out will turn clear. When the water becomes clear your filter is good to go! REMINDER after backwashing you should put your filter in “rinse mode” for an additional 30 seconds!