Additives

[christyf5]

To start with I'd just do regular water changes at first, with not many corals in the tank that require calcium, general waterchanges should be able to keep up. As you add more calcium loving corals, you will want to supplement with perhaps a two part solution for calcium and alkalinity or use seperate supplements for each. You can monitor the calcium uptake of your corals with a test kit as you increase their populations in the tank. Test kits for each of these also come in handy but if you dont' want to spend the money on them (at first, but its really nice having them at home) you can probably have your water tested at your local fish store I wouldn't dose iodine or strontium without a test kit, usually your salt mix will keep these levels in check.

I have used Kent calcium and superbuffer dkH to regulate my calcium and alkalinity levels as well as the Seachem products (liquid calcium and reef carbonate) and a new line by Tailored Aquatics (a local company) reef dkH plus and reef calcium plus.

[Canuckgod420]

I agree what christyf5 says....except for the fact that not all salts are created egual.....so that being said, if you use Instant Ocean you have to add calcium and magnesium right off the bat.
I think kent has decent levels of that stuff but their alkalinity is low...i think?
cant remember, havent used it in a while.
Also if I'm not mistaken you have to keep your calcium levels up if you want good coraline growth.
Good luck with the setup.