Crystal Pool (PVT) Ltd. Sangabo Mawatha, Anuradhapura 0716552500 crystalpool.lk Sand filters are cleaned by backwashing, which entails reversing the water movement in the filter, and flushing the filthy water into a waste line. MG Pools is really a tailor made pool and out of doors residing design build company https://www.google.com/maps?cid=3232803549851328223