what are all the additives to a reef tank?
Regular water changes will replace any lost or used supplements. Adding them seperately such as calcium or iodine is done for cases where the tank is using them faster than they are being replaced. Large tanks such as 150 gallon or 210 gallon would need very large water changes. In these cases, it can be easier to add supplements and reduce water changes. In your case, with a 60 gallon tank that holds roughly 50 gallons of water with the sand and rock, you only need to be doing 5 gallon water changes each week. You would have no reason to be adding anything. Since calcium is the number one added supplement, you can be safe to go with that as your first test additive. If your calcium is not dropping then everything else is also not dropping and you shouldn't even worry about testing for it.
The chemicals you will need all depends on the species of invertebrates you want to get. And the price also depends on that as well.
