Originally Posted by patandlace
Calcium, Alkalinity or carbonate hardness and magnesium. And of course salinity.
These are your main specs to be aware of when starting and maintaining a reef.
Of course, your basics are important as well. PH, Ammonia, nitrate, and nitrite. Once these are in check then test for the others.
Your flow is also important. Corals need more flow than just fish. This does more than just move water, it supplies them food, as well as get rid of dietrus.