Sand is perhaps the most popular filter medium. Sand is a perpetual filtration medium that rarely needs replacing, a feature that you may find attractive. Sand filters are exceptionally easy to maintain and operate; they also work well in most pool applications. One drawback of sand filters, though, is that they can allow finer particles to pass through the circulation system. Most sand filters can trap dirt particles that are 25 micrometers in size and larger - particles that are 35 micrometers or larger are visible to the naked eye; a grain of common table salt is about 90 micrometers and human hair is 70 micrometers. By comparison, DE filters can screen out particles that are approximately 3 micrometers in size, and cartridge filters can trap dirt that is 5 to 10 micrometers.

Backwashing is the term used to describe the cleaning of the sand system, and it refers to the reversal of the flow of water in order to push the accumulated dirt in the filter tank out to waste. Most residential pools use high-rate sand filtration, which utilizes the entire depth of the sand to trap dirt. DE and cartridge filters utilize only the surface of the medium to collect dirt.

Water Chemistry • Popular Disinfectants • Chorine • Calcium Hypochorite • Sodium Hypochlorite • Stabilized Chlorines •
Bromine • Other Disinfectants • Water Balance • pH • Total Alkalinity • Calcium Hardness • Total Dissolved Solids •
Balancing Pool Water • Water Testing • Pool Vacs & Sweepers •

Pool Maintenance • Daily Chores • Weekly Chores • Solving Common Problems • Cloudy, Milky Water • Malodorous, Irritating Water
Green Water • Red or Brown Water • Blue - Green Water • Blue or Black Water • Pump Problems • Sand in Pool •
Excessive Water Loss • Excessive Foaming