Filtration —key to a healthy pool

Press, 26 November 1980, Page 20

Filtration —key to a healthy pool

An efficient filter system is the key to' a healthy, sparkling pool. - Along with chemical treatment and vacuuming, it keeps the pool hygienic and attractive by mixing sanitising, chemicals and cleaning out debris. There are four parts to the system: the filter tank itself, a pump with a strainer, an automatic surface skimmer and piping for recirculation.

High rate sand filters are the most popular for home pools in New Zealand. The pool water is pushed through special

grades of sand from which the dirt needs to be backwashed at regular intervals. Waste water from this operation is disposed of through a sewer system, storm drain or dry well, depending on local council and drainage board regulations.

Coagulant additives are available to encourage particles to stick together in the pool water for easier removal • by the filter system.' ’

Heavier rubbish particles that settle on the bottom .are most commonly removed by vacuuming. The hose for this fits into the filter system

through an attachment in the skimmer, so the pool does not have to be emptied to clean its floor. Pool plumbing is designed to circulate all the water through the filter. It is drawn off through the main drain and the surface skimmer to the filter and heater, and returned through carefully positioned inlets. Suction and return lines need to be- of adequate size for efficient circulation and two or three return lines are best to keep water moving through the pool.

The size of the pump and motor is dictated by the volume of water, the

filtration rate and the pressure at which the pump must perform. The pump is best located not more than half a

metre above pool water level and within 15m of the pool edge, although it must be protected from water splash.