Hi Nora,
Also just a note that its preferable to ensure that the sand particles have diameters of 2mm or less. Some coarser,unequal sized sand grains approaching small gravel in size, can still pose an impaction risk.
Ian gave a fantastic tip about giving the sand substrate occasional 'stirrings'. You can also help minimise gas accumulation by filling up till only an inch deep of sand.
Because pool filter sand pack so tightly, some types of aquatic plants cannot 'root' properly, and thus some plants will actually die. The plants will still some level of substrate 'aeration' for their roots to grow healthily and acquire nutrients. I would recommend you get plants that are already affixed to rocks or driftwood etc.
Some beginner hardy plants species you can try are Anubias, Java fern, Java moss, some amazon swords and Elodea. Among these, anubias, java moss and amazon swords are quite readily available already mounted on driftwood or rocks.
Cheers.