The answer will depend on many different factors such as what animals you plan to keep and how often and how much you plan to do water changes. The best thing you can do is get the necessary test kits to monitor what is going on with your water chemistry and get some idea of what, if anything, you need to add. Most likely, you will need calcium and buffer, but only testing for these will tell you. As for the other additives, regular water changes should keep most of your major and minor elements in line. Some people like to add iodine supplements, others will tell you it's a waste of time. Your test kits will tell you alot, and your animals can tell you volumes. Take it slow, observe closely and be cautious about anyones new miracle fix-all.
