For Bromelia you need rainwater, and if you don't have it, what can I use?
Dear Gian Franco,
the bromeliads prefer to be watered with rainwater, if you do not have the possibility of collecting it, you can use demineralized water, or the mineral water you find in the bottle, or you can fill the watering can and leave it to rest for at least 12 hours before watering, so that the mineral salts it contains can decant, simply by falling to the bottom of the watering can; being a single plant, and I think it is not of gigantic size, it is a quietly feasible operation.
Bromeliads in nature develop in tropical forests, characterized by a hot and humid climate, and live on the trunk of tall trees, among the folds that form at the intersection of the branches, for example; for this reason their roots are not used to receiving the water that is usually present in the soil, which contains many mineral salts, obtained from soil leaching; instead they absorb the humidity of the air with the leaves, or receive water from precipitation. For this reason they do not like heavy waters, which contain a lot of limestone, a very common substance in the water of the aqueduct.
In fact, if you were to water your bromelia with tap water a few times in a row, the plant should not suffer dramatically; clear that you will find better with poor water in minerals.
If you water it by filling the cup made up of the rigid leaves, gathered in a rosette, the calcareous water will tend over time to form deposits on the foliage, definitely ugly to see.
Bromeliads are plants that are resistant, and not very demanding, they can easily withstand even adverse conditions, and even occasional watering with strongly calcareous water; they do not like dry air, so in addition to watering your plant, remember to spray it often, in order to increase the environmental humidity.
If you happen to water your bromelia with tap water for an extended period of time, remember to periodically empty the cup between the leaves, so as to prevent the development of mold or bacteria.
In summer, if possible, place your plant outdoors, on the terrace or on the window sill, in a very bright area, well ventilated and not directly affected by sunlight, especially during the hottest hours of the day; if you can put it in an area that is exposed to the elements, so you can find the water you need by yourself.