We visited with our daughter and her 2 children, 8 years old and 11 months old, so we were using a stroller. My wife and I took the 8 year old up the loooong escalator and my daughter and the 11 month old took the elevator.
The issue is that the route starts at the TOP of the aquarium and flows downward. This is fine but the elevator had stops at each level and didn't indicate to my daughter where to START.
So she got off on the 2nd level and was dumped into the middle of the route. She called me and we figured out what had happened to her. She opposed the traffic to rendezvous with us near the top.
While it appears that there is a zig-zag ramp from the top to the bottom the route actually diverts into galleries that wrap around the central core.
The whole aquarium is DARK and the intended route is poorly marked. The route markings aren't normally so important but were with our confusion.
Their web site is here and the TripAdvisor reviews are here.