Originally Posted by
Klondyke
No, it will not necesserily. Firstly, the pressure from the city system is not always strong enough to go thru the sand. Secondly, any long water storage in the tank will result in a settlement of residua that always such water contains. And the pump could pull some fine sand pieces from the filter, not so good for its bearings.
Then, it is advisable, to add timely a bit of chlorine into the tank to prevent growing of some bacterias that always can appear with such long storage - and with a unknown water quality either. And the chlorine will pull out some substances (metalic and alkalines ones) from the water. They will actually settle, however, a portion can be pulled into the system, so better to filter it out.
Such sand filter 1 - 1.5 m high standing with a backwashing valves combination (for backwashing every 1 -2 months) can be bought for ca. 10,000 Baht, and it is for your lifetime (almost), shown at many moo baan houses.