What is the alk of the salt water you are using for a water change? Most times if you just stop dosing anything the alk will drop over a few days or a week or so.
Yes, how did it get that high?
Also, be warned.... many of the Salifert alk test kits produce bad readings. I get 11 on my new salifert, 9.2 on my old salifert and 9 on my Lamotte.
i also had problems with salifert's alk test kit and if you do a search on RC there is a bad batch.........i don't remember the lot# but it produces high readings