As to why I have freshwater Aquarium as apposed to a saltwater one.....
I got my first real aquarium in the early 1970s
Back then, stetting up a saltwater tank was much more involved as there was no pre packaged "sea water" like there is now.
You had to add you own chemicals and keep testing it to see if it was finally safe for salt water fish,
It is of course much simpler now of course,
When I got back into having a tank again I chose a fresh water tank as that is what I am familiar with. :