The pool is 1,013 m (3,323 ft) long,[4] covering 8.2 ha (20 acres),[4] containing some 250 million litres (66 million US gallons)[5] of seawater, with a maximum depth of 3.5 m (11.5 ft).[6] The water is pumped from the adjacent Pacific Ocean, then filtered and treated.
The area was likely not naturally suitable for guests due to waves, currents, and marine life, so they made a sea water lagoon with beach.
I read the link included by OP.
The area was likely not naturally suitable for guests due to waves, currents, and marine life, so they made a sea water lagoon with beach.