Crystal Pool (PVT) Ltd. Sangabo Mawatha, Anuradhapura 0716552500 crystalpool.lk Sand filters are cleaned by backwashing, which consists of reversing the drinking water circulation with the filter, and flushing the dirty water right into a squander line. Considered one of the greatest trends in out of doors design right now https://www.google.com/maps?cid=3232803549851328223