Better be safe than sorry !
In the long run, hard water can damage the crystal and leave a water line on the upper part of the vase.
If there is no mineral water available, it is recommended to change the water level daily when changing the water.
If your vase is heavy and bulky, and thus difficult to move, we suggest to not fill up the vase completely but to add water or even ice cubes on a daily basis.
Clean them with a soft cloth.
Anti-static detergents help to protect the items from dust