Your shop advised you badly.
If you were going to add salt, this is a seriously unregulated way of doing it. How do you know how much has gone in? You'd need to sit down with a calculator and work out how much has dissolved, how much removed in water changes, and so on.
RTR has a fine article (rapidly becoming virtually fishkeeping internet Scripture) at http://www.aaquaria.com/aquasource/salt.shtml which examines the salt question, the myths and some actual facts.
If you were going to add salt, this is a seriously unregulated way of doing it. How do you know how much has gone in? You'd need to sit down with a calculator and work out how much has dissolved, how much removed in water changes, and so on.
RTR has a fine article (rapidly becoming virtually fishkeeping internet Scripture) at http://www.aaquaria.com/aquasource/salt.shtml which examines the salt question, the myths and some actual facts.