Not necessary and not the right way to think about “levels” in the tank.
If you are going to use water changes to keep the nutrients low the let the salt mix keep your tank salt levels the same to avoid constantly having to adjust fresh mixed salt to match the elevated salt in the tank.
If you start adding any “salt” it should be Calcium and alkalinity, and occasionally magnesium. Two corals are not going to remove mg that quick, but alk and ca are used relatively quickly.
1300 Mg is fine. I would bump it up when/ if it moves closer to 1200.
Unless you are dealing with algae, some people move it up to 1500 for Bryopsis?