Crystal Pool (PVT) Ltd. Sangabo Mawatha, Anuradhapura 0716552500 crystalpool.lk Sand filters are cleaned by backwashing, which entails reversing the drinking water movement from the filter, and flushing the soiled water into a waste line. MG Pools is really a tailor made pool and outdoor dwelling design build agency serving https://www.google.com/maps?cid=3232803549851328223