Provenance of the sea water in the Oceanium educational display (Nov 10th, 2018)

I did a little bit of research on the topic of sourcing sea water for zoos and aquaria, and apparently there's quite a few ways zoos and aquaria get their sea water. Some (mostly zoos located in or near cities with large sea ports, I guess, like Rotterdam and Antwerp) get it from the ballast tanks of ocean-faring vessels, some zoos near the sea or saltwater estuarine areas source it directly from the sea or from estuaries (Antwerp, in addition to water from ships, Nausicaa, SeaLife Blankenberge). Some that are located further inland and would require lots of road transport of sea water make their own artificial sea water from tap water, chemicals, minerals and salt (i.e. Burgers' Zoo).