Just one thing, confined water will have a definition by certifying agency - it's not always a pool.
An example of a definition:
"Confined water is a general term that refers to either a swimming pool or confined open water.
Confined open water is an open water site that offers swimming pool-like conditions with respect to clarity, calmness and depth. It has both shallow water and water sufficiently deep to allow student divers to meet all skill performance requirements.
Evaluate confined open water conditions carefully before each dive because a site may qualify as “pool-like” on a given day under certain conditions, but not qualify under others.
When confined water logistics aren’t ideal and the depth is too shallow to conduct all skills, introduce skills requiring water too deep in which to stand, in sequence, in shallow water. Then, when you have access to confined water deep enough to meet skill performance requirements, repeat the deep-water skills, in sequence, before the associated open water dive."
Here in Cozumel we commonly do confined water dives in the ocean but follow those standards.