Levels of bacteria and viruses in swimming pool water must be kept low to prevent the spread of diseases and pathogens. Bacteria, algae and insect larvae can enter the pool if water is not properly sanitized. Pumps, mechanical filters, and disinfectants are often used to sanitize the water. There are two types of filtration systems for swimming pools.
The cartridge filter on the right, on so commonly used on pools
The sand filter on the top left, is the commonly one been used on swimming pools. The round grey housing is where the sand is kept in. the sand been used is a #20 silica sand, 4.5 to 5.5 mm big. It is specially graded to trap particles in the 20 – 100 micro range. This filter is suitable for out side pools because it is designed to trap leaves, sticks, flowers, insects and any solid objects. The multi port valve allow you to clean the sand by putting it on backwash. By doing it regularly the sand can last up to 2 years.
The cartridge filter on the top right, is not a commonly used on pools. Different sizes of the filters are available for the different sizes of swimming pools. These cartridge filter will on inside pools, Jacuzzis and out side pools where there is no lawn, plants or trees around the pool. This filter can also be remove and cleaned several times with an hosepipe before it need to be changed. A pressure gauge is mounted on the housing to let you know when the filter been blocked.