Have you dosed anything in the past? do you know what your salt base levels are for cal and mag? I don't see how your cal and mag got so high without dosing unless your salt has levels that high. or the salt itself isn't well mixed before adding water? Can you mix up some fresh saltwater and test it before adding to your tank? Something is out of whack and it doesn't make sense. The only other issued could be what you are using to test with.
best way to even out all your parameters will be to do some larger water changes. But you need to test the fresh saltwater first. Once you obtain a balance of ph, alk
, and cal your system should balance out and stay stable with water changes and or dosing. Do you have a large lps
stock? If not you shouldn't need to dose unless you don't do water changes.