Crystal Pool (PVT) Ltd. Sangabo Mawatha, Anuradhapura 0716552500 crystalpool.lk Sand filters are cleaned by backwashing, which entails reversing the water movement with the filter, and flushing the dirty water into a waste line. We design architectural plans for swimming pools, preparation of costing Monthly bill of Portions (B.O.Q.) and https://directoryholiday.com/listings12833579/the-ultimate-guide-to-swimming-pool-circulation