Interesting, I didn't realize Delbeek left Waikiki this year to go work at the new Steinhart Aquarium. Man, I think I'm totally going there after it opens later this month!!
... I think the rainwater/evaporation isn't a problem for the Waikiki outdoor aquarium because the turnover from natural seawater is probably large enough to compensate. (Their source water is a well which brings in pristine seawater from underground.)
And that surge tank is the granddaddy of them all. Bruce Carlson's legacy
(hence the term "Carlson surge").
I've never been to the Waikiki aquarium but I'm totally going if I ever make it to Oahu.