MG Ca kh and alk all off

What kind of salt are you using? I agree with the wait about a month, but during that month you must keep your ALK levels under control. During this month I may also try to slowly (over a week or more) bring alk up to around 15 or 16 dKH that should both bring CAL down and it should help with the cal/alk balanced "relationship." With this balanced relationship the levels should fall together to the range you want, but bringing high cal down and keeping alk on the low side is a very long and difficult task.