Calcium levels driving me nuts

[Farrmanchu]

Originally Posted by bassman

I do have a fair amount of coraline growing on my rocks and glass right now. Tank is only 6.5 months old.

How's the Coral growth? Are you trying to achieve faster SPS growth, Coraline? If you've noticed good growth, why worry about getting Ca over 400ppm?

[bassman]

Originally Posted by Farrmanchu

How's the Coral growth? Are you trying to achieve faster SPS growth, Coraline? If you've noticed good growth, why worry about getting Ca over 400ppm?

I have read that 440ppm is a good place to be, as in healthy all around. I also have a clam which need high calcium. Atleast that is my understanding.

[Aquattro]

Calcium should be between 350 and 400 for good growth. Natural seawater is about 350ppm, and we keep it slightly higher just in case levels drop. I have always had awesome SPS growth with Ca around 390ppm. I have had my level higher, but did not see increased growth because of it. I keep my alk around 9-11 dKh, never concerned my self with Mg.

[bassman]

I think I will try a salt with a higher calcium level. Right now I am using Instant Ocean. I think I will try Reef Crystals and see what happens. I tested my makeup water last week B4 adding it to the tank and the calcium level was below 400, somewhere around 330 or something like that. This plus dripping kalk might be enough.

[untamed]

Don't mess things up by trying to achieve a number like 450 just because you've heard that is a good place to be. If you system looks happy with what you are doing, you're just as likely to cause problems trying to force it upward.

Shoot for stability in Ca/Alk/Mg. With a Kalk based system, you are likely to need to dose Mg somehow. Increase the Kalk only until the Ca/Alk is stable (not falling). If your growth (demand) increases, you might have to adjust your Kalk input to match.

In my experience, you need to isolate evaporative replacement from Kalk input. As evaporation changes all the time, you don't want your Kalk input to be also changing. I think Kalk for evaporative replacement works well if you also have a Ca reactor running...but if Kalk is your primary Ca/Alk replacement, you want to control it's input as much as possible.

That's my $.02 worth from running a Kalk-only 30 gallon SPS based system for a few years now. My Ca rarely every gets higher than 385.

[bassman]

Thanks for the insight. I think I will take your advice. Like I said I am going to use Reef Crystal and see what that does. Other then that I think I will leave well enough alone for a while, track my levels and see how things go.