This is from allearsnet:
There are two pools at All Star Music. The main pool located between the Calypso buildings is the Guitar Pool, so named for the shape it is in. The Kiddie Pool is also located here. The Guitar Pool is not a zero entry pool. It has stairs used to enter on either end of the pool. The maximum water depth is 5 feet and the minimum is 3 feet. There is a squirting fountain on a raised island in the middle of this pool that features the characters from Disney's "The Three Caballeros".
The quieter pool is the Grand Piano Pool located between Rock Inn, Country Fair and Broadway. The Grand Piano Pool is also not a zero entry pool. It, too, has stairs to enter and exit on.
Both pools list their hours as 8:00 am to 12:00 midnight, but this may change depending on season. Security personnel have been know to remove noisy guests from the pools after midnight. Lifeguards are on duty at both pools daily.
I was just told by a CM at ASMU that the hours are 7-midnight, not 8-midnight. Maybe the pools open earlier in August.