The short answer
A saltwater pool is not chlorine-free. The system passes salty pool water through a cell that generates chlorine, which sanitizes the water before eventually returning to salt in an ongoing cycle.
The generator does not manage the whole pool
The system's output can be affected by water temperature, salt level, cell condition, scale, circulation, run time, swimmer use, weather, and the pool's chlorine demand. Owners still need to test the water and confirm that the system is producing enough sanitizer.
pH and water balance still matter
Saltwater pools commonly require active pH management. Water balance should also consider the pool surface, equipment, calcium, alkalinity, stabilizer, and other conditions rather than focusing only on the salt reading.
Cells require inspection and eventually wear out
Scale can reduce cell performance, and every cell has a finite service life. Cleaning or replacement should be based on actual condition and manufacturer guidance, not performed automatically without evaluation.