Rinse it very well in a bucket, until the water is clear. Drain some water out of your tank, as the sand will displace water as it enters the aquarium, turn your filters off, choose one of the following: 1.) Dump sand in 2.) Lower sand to bottom of tank in bucket and gently place sand 3.) Throw fist fulls of sand at the bottom of the tank..... There really is no right or wrong, just rinse, turn off filters, dump sand in, wait til sand settles, turn filters on and you have a sand bottom tank now.