Depends. With all the interactive feedings I would say three hours.
We spent there 7 hours with my 11 years old son. But mostly because we watched 3 movies and saw 3 feeding session. Plus lunch and tea time breaks...
We just got back. We got in just before 10:30, ate lunch at a restaurant outside the aquarium. We watched 2 feeding. We left at 4:30.
There are area specific group tours but no whole show type tours. There is a lot to see, and it's set up to lead you through the exhibits one by one while still allowing you to skip stuff (like if you don't want to go to the pool where you can touch a starfish or whatever). Adults probably 2-2.5 hours. With kids 3+ hours.
Recommendation is 4 hrs which included lunch and two feedings
There was no tour, not sure if those are available. You go where you want and take as long as you want in each exhibit. We spend 3 hours there and saw mostly everything including a short break to eat.
It's up to you to explore the aquarium at your own pace. I would think 3-4 hours if you just walk it, more if you choose to watch them feed at the exhibits, watch one of the films, etc.
Thanks! Your answer is awaiting moderation.