The friendliest place on the web for anyone with an interest in aquariums or fish keeping!
If you have answers, please help by responding to the unanswered posts.
Unless you only do water changes once every 6 months I doubt it's anything to worry about. Just make sure you're using a refractometer so that your water for changes has the correct sg. An inaccurate hydrometer could possibly make this an issue if it's giving you false high readings.
Like Atari said, just watch the SG with a refractomoter and if it goes down a bit top off with SW not fresh. But salt cannot creep that fast. If you let the salt build up too much, it can break off and cause problems by dropping large crystals into the water.