The lining now needs to be covered with a protective layer similar to the one already below it i.e. newspapers, carpets, etc. (Note: avoid using red carpet - the dye may come out, turning the water bright red!). This covering protects the lining from the sun. Now cover this layer with an overlayer (about 100 mm) of subsoil or gravel - you can use some of the soil you have dug out. Remove the weights from around the liner, securely anchoring it down under 150 mm of soil all around the edge.