[Mekatra]

Because of the science behind salt water pool filters they're actually cleaner bacteria wise than a traditional one.
Science:

Salt-water pool disinfection systems rely on chlorine to kill germs and neutralize contaminants in the water, just as traditional chlorine-based systems. A unit containing two slightly charged titanium plates allows the salt or NaCl to pass through them. In a process called electrolysis, the salt breaks down and reforms in water to form the hypochlorous acid responsible for disinfection in traditional chlorine-based systems. Because the salt is dissolved in the pool water, there is a continuous and steady supply of chlorine flowing into the pool.