When buying a new RO water purifier system consumer often comes across this question of whether they should have an external pre filter or not. The pre filter is a primary filter which is used to separate the bigger sand and sediment filters before a RO system. It increases the life of filters inside the RO and since it is installed outside, so it can be changed easily and frequently without opening the whole RO purifier. It comes in some varieties, and generally consumers are charged excessively for the same. We have pre filter starting from 399 only. Here you can get different varieties of pre-filter like as Kent, aqua fresh, blue life, and Spun pre filter etc. For high rise buildings in housing societies heavy duty pre filters which can withstand high water inlet pressure. Also there are transparent pre filters available so that one may come to know when a filter gets dirty (brownish) visibly and can change it. Inside the filter housing is a 5 micron spun filter or a 9 inch candle, which is used by Eureka Forbes Aquaguard also. This 9 inch candle has carbon also to separate the chemical and other smells from the water.
How often should the pre filter candle be changed?
The pre filter candle should be changed as often as needed, however depending upon the consumption and quality of input water, it may be affected. The average time for a domestic pre filter to be changed is around 3 months. However it can even be 1 month if the water is muddy. This can be known by taking out the candle and it should be light brown if it is black or very dark brown you should change it more often. The candle getting brown is not a sign that it is of low quality, in fact its job is to absorb as much mud as possible so that the main inline filters, carbon and sediment and the membrane are not affected. You can also put Antiscalant balls or stick in it for improving life of membrane.