4 ms·A slow sand filter requires water that is not salty. A desalination device serves a different purpose.by adrianN 4y agoA slow sand filter requires water that is not salty. A desalination device serves a different purpose.collyw 4y agoI know off of the top of my head how to make a very basic solar still.adrianN 4y agoThe device in the article is a slightly less basic solar still.