"We noticed that the shower was getting white spots where the water comes out. We isolated it with a plastic bag, and after a week this white powder accumulated. Is it something added to treat the water?"
A: "Probably Limescale. Mineral buildup in hard water. Typically harmless, but that looks like a lot of that’s what it is."
To remove the scale that's already there, just soak the faucets in simple lemon juice, available at any grocery store. Cheap, no harsh chemicals. Wipe away scale after 30 minutes.
https://earth.google.com/web/@-54.66239115,-36.19531314,957.24274773a,559.044623
66d,35y,0.11594552h,0t,0r
The beacon says "UFO crash"