You can always drain, fill with distilled water and a little bit of coolant (100ml or so) and flush several times until the approximate water content...
Yes you gotta tighten the tension bolt bit should loosen the two nuts holding it place first. I wasn’t very clear and mentioned doing it with the car...
Welcome. It seems like every country has different specs/options for each model. The Canada and US models differ a lot and same goes for Puerto Rico...