Corals when do i add Calcium?

[imfsub12]

Yes i'm starting to get some more corals..
I currently have a Colt coral, 2 mushrooms, and 2 Ricordea
Will be getting a Torch Coral and may be a Hammer head and a frogspawn..
Do i need to start to add calcium to my tank.. I don't' currently test for it neither..
thanks

 

[veni vidi vici]

In addition to testing for Ammonia,Nitrate,Nitrite and PH.Your gonna want to start testing Calcium,Alkalinity And Magnesium.Hard corals will be using these Calcium and Alkalinity for growth and Magnesium to keep the Calcium and Alkalinity stable.
Typical natural seawater has a natural SG of 34-36 ppt
sg = 1.025-1.027
Calcium = 420 ppm
Alkalinity = 2.5 meq/L---7 dKH---125 ppm CaCO3 equivalents
Magnesium = 1280 ppm.
Your going to want to stay around these numbers.As you add more LPS/SPS the demand for these elements is going to increase so at some point you will probably have to suppliment. I would start testing and see if water changes will keep you where you need to be for now.