Swimming pool filter is like the kidneys of your body.Both require a suitable pump to deliver an adequate water flow through them to enable satisfactory filtration. A correctly sized and operated swimming pool filter will provide the most cost effective method of ensuring clear, clean and healthy pool water.
In Australia there are essentially two types of filter systems available, Sand Filters and Cartridge Filters. Each have pros and cons and the choice for either is both personal and/or job specific.
How They Work
Pool filters Sydney relies on the pump to deliver the correct amount of flow to ensure optimum effectiveness in removing debris and impurities contained in the pool water. Each of the filter types will continue to clean the pool water and in the process, increase the resistance to water flow over time. The pressure displayed on the filter will increase to a point where the filter media will need to be cleaned.
Cartridge Filters have a media that consists of a cartridge element. The element is designed and made from a material called Remay that provides a large surface area in which to trap debris. Cartridge elements cannot be backwashed, to clean they must be periodically removed and hosed down. Once clean, the element is replaced and the operating pressure is once again lower.
Sand Filters have a granular sand type media. The sand is normally 16/30grade sand but you will find different media suitable for use such as Zeolite or Glass media. A sand filter does not have a large surface area such as a cartridge filter in which to trap debris but overcomes this limitation to a degree by the ease in which it is cleaned. The image below illustrates how water flows through the sand media during filtration. A pressure increase in the filter is proportional to the debris trapped in the media. Once the pressure reaches the design maximum, the filter is Backwashed to clean the media. Backwashing is a procedure controlled by a multiport valve (MPV). The water flow is reversed for approx. 3 minutes to lift the dirt from the sand and deliver it down a waste line. This procedure cleans the media. Immediately afterwards, the MPV is used to perform a 30 second rinse. Rinsing is the procedure where the sand media is bedded back down and all the loose debris is flushed to the waste line and not back to the pool on start up.