How come you don't even mention the large Olympic sandbeach/waterpool area in the Chaoyang park in Beijing?
It's like reviewing Beijing's attractions and "forgetting" the Forbidden City.
And for these indoor pools - there are over a hundred of them in BJ when I checked, in public schools, fitness clubs, living compounds, etc (e.g there are three 50m pools in 10min walk from my office, there are three 25m pools in 10 min walk from my living place). You seemingly arbitrarily pick 5 and call them "best".