One of the largest in the world at 750.000 liters. I have actually visited the behind-the-scenes area above this tank twice during behind-the-scenes tours and it is at least as impressive as the tank itself.
I can believe the behind the scenes facilities for a reef like this must be something else. Largelly why so many aquariums cheap out and go with gaudy fake corals is because its so complex and expensive to run real coral reef exhibits like this. Especially if they are inland and cant pump real seawater.
@DelacoursLangur I have actually visited the behind the scenes facilities of Burgers' Ocean twice and they are very impressive, at least as impressive as the aquarium itself I would say. With regards to the facilities of this living reef: they have both skylights and a very impressive array of high-powered, specialized lights above this tank. The filtration equipment of Burgers' Ocean was also of pretty impressive dimensions. Another very impressive view I remember was that above the large shark tank, which is actually substantially larger still than it looks from the public area. I have photos of the Ocean behind the scenes but unfortunately I believe I am not allowed to show them publicly anywhere.
On the matter of sea water sourcing: Burgers' Zoo is in the East of the Netherlands and pretty far from the sea on the scale of the low countries. Burgers' Zoo does not import sea water, they make there own on site from fresh water (I don't know if it's tap water or ground water though), marine salt and mineral elements.
To compare: The other major aquarium in the Netherlands, Rotterdam, is located in a port city and they have their own boat to procure sea water from the ballast tanks of large ocean ships in the port.
@DelacoursLangur That way they can get their hands on rather pure water from Newfoundland instead of dirty North-Sea water. Interesting to compare: Blijdorp changes 10% every month whilst Burgers changes 5% every year. On the other hand Blijdorp also has some other enclosures (sealion, polar bear, possibly also penguin) on the same circuit doing a circle of most pristine (coral-reef) to less pristine (fish tanks) to not pristine (mammals) and via filtration back to the first.
@KevinB Normally saltwater is made from reverse-osmosis water or some other form of purified water, so wether they source it from own ground water or tap water (which is most probably also ground water) doesn't really matter.
@Jarne Very interesting insight thank you. That is a surprisingly small water change when compared to most privately held systems, although I imagine the vast size of some of these tanks means that any waste is significantly more diluted. Its also very interesting that they cycle the water from cleanest to dirtiest within the same filtration system. It makes sense, I guess I always just assumed that they would have separate systems for different areas to lower the risk of a site wide catastrophe.
Blijdorp normally has it all (or nearly all) on one system. Burgers' I'm not sure of, they might have different systems. Burgers' Ocean is quite new (2001 I believe) and they are known for high-quality setups so it's not surprising that they change so little. Unlike most aquaria, Burgers' tanks are also lowly stocked. Antwerp has only 5 systems, 3 saltwater (warm, cold and the big recent reef tank) and 2 freshwater (warm, cold).
Compared to home aquaria some of the public aquaria like Burgers' are stocked less dense, but I have my doubts about many smaller tanks in other aquaria. In Antwerp, Artis, Duisburg and Blijdorp at least, a lot of tanks aren't less stocked then many private tanks.
On second thought, I'm quite sure Blijdorp has 3 systems. Cold saltwater (the north-sea section, bass rock, sea lions, penguins and polar bears), warm saltwater (real reef, fake reefs, mangrove tanks) and warm freshwater. Amazonia might have a separate filtration system for their tanks.
