Additives

[Reefman29]

What additives should I being using and how often? Tank is a 75 gallon with about a 10 gallon sump. I will be keeping a variety of corals and a clam or two.

 

[Randy Holmes-Farley]

Mostly just something for calcium and alkalinity, at least for a start, unless you have specific needs, such as iron for macroalgae or silicate for sponges.

This has more:

The “How To” Guide to Reef Aquarium Chemistry for Beginners, Part 2: What Chemicals Must be Supplemented
http://reefkeeping.com/issues/2007-04/rhf/index.php