Question 1, Calcium

[steve-s]

Originally Posted by danny zubot

My question is; do corals actually get used to higher calcium levels and develop a higher appitite for is over time?

Really depends on the coral, it's not a generalized answer. Only scleractinians will be a concern and of those, only "SPS" are really a factor. Euphyllia, Faviids and the like are so slow growing to begin with that elevations above NSW values will not make much of a difference.

When it comes to "SPS' in particular, the problem is they have a specific level that they strive for, loosely being 410-420 ppm to keep equilibrium with their cells. The coral is constantly depositing the Ca it takes in to rid itself of it. When the level of Ca is artificially raised above that, the coral has to work harder to deposit more Ca. In doing so, it cannot easily match the rate of skelatal growth to tissue growth which is where the stress comes in. More commonly a tank running very smoothly will not have much if (m)any issues except for thin reedy growth. Due to the continual stress of the higher Ca, any upset can easily cause a stress event in the coral it would otherwise be able to deal with. If the higher Ca uses up much of it's already low reserves of energy, there's nothing left when a stress event (temp, pH, salinity etc) comes into play.

http://www.findarticles.com/p/articl...02/ai_n8850134

http://jeb.biologists.org/cgi/content/full/205/14/2107

http://www.advancedaquarist.com/issu...2004/media.htm

http://aslo.org/phd/disccrs/200206-4.html

Cheers
Steve

[Beverly]

Sam,

Reading a little further into the article you posted, I found .....

http://www.advancedaquarist.com/issues/nov2002/chem.htm

Recommended Ranges

Before getting into problems and solutions, let’s first define what constitutes a problem and what does not. Based on published studies3 involving the calcification of corals and other organisms, I recommend the following:

Alkalinity: (due to bicarbonate and carbonate but not borate, so those using Seachem salt must raise this value substantially to accommodate the borate being counted in standard alkalinity tests)

2.5 - 4 meq/L or 7 - 11 dKH or 125 - 200 ppm CaCO3 equivalents

Calcium:

380 – 450 ppm calcium ion or 950 - 1125 ppm CaCO3 equivalents

If you are anywhere within these ranges for both parameters, you do not need to perform any correction on your tank chemistry, though you may choose to do so for other reasons. In this sense it makes no difference what the relationship is between the two values. If alkalinity is 4 meq/L, it is not inherently any “better” for calcium to be at 380 ppm or 450 ppm. Also, these ranges are somewhat arbitrary, especially at the high end. In fact, the primary reason for having a high end at all is that it is often difficult to keep one of these parameters above the minimum end of the range if the other is over the top end. So if one of these parameters is slightly above the high end, and the other is OK, that is not a problem worth worrying about.

So if I go by what the ranges are, I'd be a bit high going to 12 dKH in alk, but it shouldn't pose too much of a problem. At least according to the quote.

[Samw]

Yeah, keeping it within the ranges is good. The problem is when Calcium is overly higher than NSW as what I assumed Steve meant. I don't mean 420-450 range but more like something over 500. In that case, Alk would be overly low. Thus slowing coral growth I assume.

[StirCrazy]

Originally Posted by Samw

Yeah, keeping it within the ranges is good. The problem is when Calcium is overly higher than NSW as what I assumed Steve meant. I don't mean 420-450 range but more like something over 500. In that case, Alk would be overly low. Thus slowing coral growth I assume.

nope I was thinking anything over 400ppm, now how much difference will 400 to 420 make?? I don't know it may be a mm every 6 months. I try to keep mine under 400 and 380 is the target.


Let me explain something first, the Ca levels I am talking about are going to depend on your Salinity also.. there is a balance for salinity VS Ca. for example if your salinity is 1.027 then your Ca should be 415ppm for the balance, higher than this and you are in the zone of diminishing returns, if your salinity is 1.023 then you are probably looking at about 360ppm for a ballanced Ca level, so if you keep the tank at 1.025 then you might want to be aiming for about 390ppm Ca


Steve

[steve-s]

Originally Posted by StirCrazy

nope I was thinking anything over 400ppm, now how much difference will 400 to 420 make?? I don't know it may be a mm every 6 months. I try to keep mine under 400 and 380 is the target.

Yup, that's what I meant in general, Ca should not actually exceed 420 ppm but in reality, the coral begins feeling stress (working harder?) at the 410-415 mark. Personally I keep mine between 400-410 ppm as a rule.

Let me explain something first, the Ca levels I am talking about are going to depend on your Salinity also.. there is a balance for salinity VS Ca. for example if your salinity is 1.027 then your Ca should be 415ppm for the balance, higher than this and you are in the zone of diminishing returns, if your salinity is 1.023 then you are probably looking at about 360ppm for a ballanced Ca level, so if you keep the tank at 1.025 then you might want to be aiming for about 390ppm Ca

Your in the right place, just might want to use a different designation. If keeping your water at 35 ppt, Ca should be 415 ppm. When you reduce the salinity by say 30 ppt, you've diluted the chemistry overall by 15% (30,000/35,000). Typically why some have problem maintaining target levels to begin with. So the 415 ppm would also be reduced by 15% giving you a value of 352.75 ppm. Same explaination, just different route to get there.

Cheers
Steve

[StirCrazy]

Originally Posted by steve-s

So the 415 ppm would also be reduced by 15% giving you a value of 352.75 ppm. Same explaination, just different route to get there.

Cheers
Steve

ya I think I had 357ppm or something.. just rounded up to 360

Steve

[Ruth]

I certainly don't profess to understand the whole chemistry thing that goes on in my tanks but I do know through trial and error and doing a whack of research what works for me and at what levels my tanks seems to do their best. I try to maintain my aquariums calcium between 420 and 440, my Mg. at 1300 to 1350 and my KH at 6.5 to 7.5. Salinity between 33 and 35ppt. I run a calcium reactor on my 2 large systems and I would highly reccommend running this piece of equipment on any larger system that you plan on keeping calcium demanding species in. I am going to try adding some magnesium granules to my reactor media next time I have to add some to see if this will eliminate the need to dose mg. On my 44g cube I do dose C-Balance 2 part solution but I find this a PITA to stay on top of and not have swings in levels. If I do find my calcium dropping (which has not happened since I brought the reactors on line) I have some Kent turbo calcium that I plan on using.
I agree with Bev that it is difficult to talk about Calcium without also discussing the balance of KH and Mg as they are all related and integral to each other.

[StirCrazy]

Originally Posted by Ruth

I am going to try adding some magnesium granules to my reactor media next time I have to add some to see if this will eliminate the need to dose mg.

Do you have a Mg drop whith the Ca reactor running? I found once I did my inital corection the Ca reactor maintained Mg also. what are these Mg crystals you are talking about?

Steve

[bv_reefer]

-i really didn't research calcium too much and know fairly little, and was wondering if there is any reason why calcium levels could be 2 high, not that it happened 2 me but just wondering, also is there such thing as too high calcium levels?

[StirCrazy]

Its not quite that simple, and to give you a real answer we need to know more info, ie. salinity, alk ect.. even type of test kit.

usaly a high Ca corasponds with a low alk but there are always exceptions.

Steve