Calcium level tolerance

[Gustavo Duarte]

What is the lower level calcium tolerance in most corals?

When they stop to grow?
When they begin to die or the calcareous matrix begins to dissolve?

 

[Anonymous]

welcome.

all i can tell you is i,ve had my calc. drop to as low as 250 ppm.i returned from a long vacation and had taken a gamble with an unexperienced tanksitter/housesitter.i checked the various chem. levels in a stressed looking tank (particularly the clams). a gasp later i was adding calcium and mixing new water for a major h20 change.all went back to normal fairly soon. probably could go lower because my alk was low as well, but i learned my lesson, and hopefully this situation doesn't replay itself.

 

[randy holmes-farley]

Calcification in some corals begins to decline at calcium concentrations below 360 ppm. Check out this article:

http://www.advancedaquarist.com/issues/apr2002/chem.htm

 

[IronChef]

On the otherside of this question what high end concentration of calcium would be considered dangerous to coral and fish? Or maybe I should ask, what is the highest someone has seen thier calcium go with little or no ill effects??

 

[tanzy]

I believe in a reef tank, the high limit of Ca level is self-limiting as it would start precipitating, unless you are dosing a lot of CaCl and your alk is very very low, I doubt it gets above 500ppm. I believe that if that happens, the pH should be off too, corals will certainly be affected.
Any chemist out there who disagree?

 

[Gustavo Duarte]

Randy

I red your very good article, and I've got others questions...

In my opinion we have two problems with calcium levels.

The level that begins to reduce growing (and, if it exist, one level that the grow stops) and the level that the calcareous substrate begins to dissolve.

In aquariums when the low calcium levels is a problem, considering these two points?

 

[Anonymous]

...the level that the calcareous substrate begins to dissolve

hi.
Dissolution is a dynamical process, and even at 1000ppm, calcium substrate will still dissolves, but the net rate is negative. With this in mind, I just want to say that if calcium substrate dissolve in your tank, you have a bigger issue with how did the system got there, and how you going to keep you coral alive in such a condition.

 

[Gustavo Duarte]

Then, the dissolution is not a problem? If we have calcium in 150 ppm, the skeleton is not going to be fragile?

 

[Anonymous]

hi.
With that low concentration, you coral will expend a great deal of its energy just to stay alive, and the fragility of the skeleton is the least of its concern.