Just for information, not necessarily a recommendation; the Grand Wailea and Four Seasons Wailea both have salt water swimming pools, and the Grand Wailea probably has the only "designed for scuba training pool" in the entire State of Hawaii.
My short stint as instructor/guide at the Grand left me with very fond memories of that training pool. My last "class" was a couple weeks ago, and all my normal "confined water" was too turbulent (due to big south swell), so all the water work was conducted from shore in Kapalua Bay. Good thing those kids were experienced ocean snorkelers!