What would cause a brand new bathtub to look like this 9 months later?

it rly doesnt depend on anything honestly and its just some water that sits there sometimes so its not like u can do much other than trying to clean it and if thats no help, then u should go to the store and ask about something to help get rid of it. if nothing works then u might wanna just buy a new tub if it is rly bugging u that much.