Explain what magnesium and calcium do for your tank

[fishyman12]

I am not sure why people buy bottle of magnesium and calcium for there reef tanks. I am thinking about starting one, what exactly do they do for the tank?

[fishyman12]

O and I almost forgot, do I need to do dosings/buy magnesium and calcium to put inn my reef tank.

[thegrun]

Hard corals and clams use calcium to build their skeletons. Magnesium primarily acts to allow water to maintain higher levels of calcium. The amount of calcium found in ocean water would not be possible to maintain (it would precipitate out of the water column as a solid) without magnesium. You usually do not need to dose either calcium or magnesium unless you keep hard corals or clams, normal water changes would replenish their levels.

[Sport507]

It's about chemistry and don't forget the ALK. Here is why.

http://www.youtube.com/watch?v=mI52IyBtjp0

[dwd5813]

some interesting reading:

http://reefkeeping.com/issues/2006-06/rhf/index.php

the vid sport posted is also a pretty good explanation.

[jlong11]

word of thought dosing calcium without doing your homework or knowing what your doing can give you very high levels of calcium that would be less than ideal for your tank and even if u have hard coral or such things u still can overdose fairly easy so be sure to read up there are also calcium reactors if your doing alot of sps if you have questions be situation specific and there will be plenty of help for you good luck-jamie

[disc1]

Short answer is that it is something you should learn about now. But you won't need to add any dosing of any sort for the first little bit with a new tank. Later on, testing your water will let you know what if anything you need to dose to your tank. Most tanks with lots of hard corals will need clacium and alkalinity. A lot will need magnesium. But in the beginning while you only have maybe a few corals, there will be no need.