Best way to clean play sand
1) get three buckets, 1gal, 3gal, and 5gal

2) fill 3gal bucket halfway and fill with water

3) dump 3gal into 1gal until full, then empty into 5gal

4) repeat steps 1) - 3) until 5gal is full

5) spread on large concrete surface to dry, the thinner the better

6) scoop all sand into sand box

7) purchase pool filter sand

8) rinse in 5gal bucket 5"-6" at a time

9) turn off filter and scoop gently into aquarium until it settles

10) consider how easy it would have been to start at 7)