I think he is concerned about the salt being brought over from the pool to the hot tub via skin and bathing suits. The amount of salt in a salt water pool 'should' be under 4,000 ppm. The little amount of salt carried out of the pool into the hot tub should be minuscule and if you are draining your hot tub a couple times of year I could not see any significant amount of salt building up in your hot tub.
If you are in a year round warm climate give your suit a hose down before you climb into the hot tub and no worries.