Efficient filter essential to pool maintenance

Press, 18 November 1981, Page 32

Efficient filter essential to pool maintenance

A good filter system is essential for a- swimming pool. . The filter enables you to use the initial water supply over and over again, adding only enough water to make up for evaporation and splashing. The size of the filter is determined by the amount of water the pool holds. During the summer,- the filter should be run 24 hours, seven days a week. In the winter, the filter should be operated for at least one day .a week. The filtration system is composed of four ’elements — the filter tank, a pump with hair and lint strainer, an automatic surface skimmer and recirculating piping. There are two major types of filters available for residential pools — high-rate sand and pressure diatomaceous earth. The high-rate filtering system is based on the concept that the high flow rates and pressures drive dirt down

through the filtering media (layers of sand and gravel). A high-rate sand filter requires between 227 and 273 litres per minute (minimum) of water to back-wash with full pump, outlet for two to three minutes. Diatomaceous earth filters demand less water for backwashing. This type of . filter strains the water through diatomaceous earth (D.E.) a sedimentary rock composed of microscopic fossil skeletons of a small water animal, the diatom. The D.E. rock is mined and then crushed, washed, sized and packed as a powder. The filter forces the water through the media similar to the high-pressure filter. The media is'probably the most important part of the filter. It is through this component that back-washing can be achieved. Filters-will have greater resistance to the water flow as dirt collects on the filter surface. Pressure gauges are generally provided to indicate this resistance and when pressure reaches . the limit recommended by the manufacturer, the filter must be back-washed by means of a reversed flow from the pool. More frequent back-wash-ing will not harm a filter. Little used pools will benefit from a regular, weekly backwash, regardless of whether pressure limits have been reached. Thorough back-washing keeps the filter clean and running efficiently. After back-washing, the water in the pool should be made up to its correct level so that proper surface skimming and circulation is re-established.