Been running my tank for about 6 months now, got 2 clown fish, cleaner shrimp and a gobby. I now want to add some soft corals to my 20 gallon tank but i was just wondering would i need to dose any elements in the tank because this confuses me and haven't done this in my tank before:headwally:. However i have heard that weekly water changes, the salt mix with provide some of this and therefore make the corals healthy along with feeding them?