sudden rise in calcium demand.

[Sk8r]

:shock: My 52 gallon tank (set up in January) has lazed along taking about 1/4 tsp calcium (with alk at 2.98-3.5, mg at 1300) about every 2 days.

Suddenly it's taking half a teaspoon a day, and maybe more than that: I'm still adjusting. I run buffer in my topoff water. I add Kent calcium beads to the sump dissolved in tank water. The buffer has tended to deplete more rapidly than previously by about a third (then I accidentally ran it a bit high), but the calcium demand is what really surprised me: it's more than doubled. More like quadrupled.

I acquired a 3-4 inch crocea, for one thing. Besides that I have frags of: 1 green bali slimer, 3 small acroporas, a mille, 2 montipora flat pieces, 3 digitatas (one as big as your fist) a 3 head hammer, a single head frogspawn, a smallish bubble, a fox, and a 2 inch plate. Now, admittingly I'm running out of places to set things that nothing else can reach, but this was quite a sudden rise in demand---like over the course of days.

Is it the clam? The corals? The mysteries of a new tank settling in? Is it going to get hungrier than this? How much is safe to add at a time? I have an inquiry in progress about kalk, and I am testing often and trying to stabilize this sudden seesaw of alk and cal. Any additional info would come welcome.

 

[DonW]

As you know things grow your ca demand is going to climb. One thing you mentioned is adding dry ca directly to the sump. Assuming this is calcium chloride, that may be your issue. It doesnt dissolve fast in SW and should be predissolved in rodi.

Don

 

[MikeS]

hmmm...what are your actual Ca/Alk levels right now? it could be an imbalance between them causing it...

MikeS

 

[Sk8r]

No, I do predissolve it, but in a little saltwater drawn from the sump.
Yesterday my calcium was 400, alk 3.5. I added 3/4 tsp calcium to the sump, predissolved.
My calcium was 320 today, alk 2.98. I added another 1/2 tsp calcium. Mg is 1300, salinity 1.025, temperature 80.3.

I remain baffled---I'm hesitant to add a whole tsp to my 52 gallon, for fear of overdoing it, since the Kent container talks about 1/4 tsp per 50 gallons, but I'm certainly not keeping up with demand.

 

[charlyclown]

You can use the reef calculator
http://home.comcast.net/~jdieck1/chem_calc3.html
to determine how much you need to add each day. Is your pH stable and how are your corals doing?

 

[fishermann]

I would do like Don says and desolve in ro/di water. but you have to keep up with demand whatever that maybe, more corals and clams more demand, I ahve never been able to figure out where these co.'s get there doses from because the more demand you have tne more you have to doses. Mike is also right one being high can keep the other down, but seems like both are going down equally.

 

[Sk8r]

They're both sinking, but the calcium is going faster. I can dissolve in ro/di, no problem, just take it from the bucket. It's just the suddenness of the change that I find curious. The corals are ecstatic: the pearl bubble extends huge sweepers, the frogspawn is puffed, ditto the rest, and the acroporas have feeders out after the lights go out, and are growing.

There is one concurrent "what's unusual." I began using Kent Coral Vite with micro-doses of minor nutrients about 3 weeks ago. Could a microdose of, say, iodine and cobalt and strontium suddenly wake things up and make the corals 'hungry?'

My uneasiness is that I might be building up chemical 'tension' in the system that will all come due at once---but with mg, alk, and cal continuing to drop (the calcium faster) at conjoined but steady rates, it still seems maybe it's going all right---but to get that calcium at 400 or better, how much dare I add? That's what has me nervous. I will use the calculator, with appreciation, and get ro/di ready for a water change.

 

[Sk8r]

The calculator is telling me to add 11 teaspoons...that can't be right. Total of 60 gallons, counting the sump---320 cal this morning. And I should add 11 teaspoons? Surely not. I must be misreading it.

 

[charlyclown]

An explanation could be that the long term use of calcium chloride increased the calcium ion concentration to such high levels that calcium carbonate precipitated from water which in turn lead to decreased alkalinity and decreased calcium. In fact, generally, calcium chloride should not be used long-term but just for small adjustments. In this case, I would do a good water change and use calcium hydroxide. For your tank, 6 teaspoons should increase calcium by about 50 ppm, but I would add 2 teaspoons first and measure two hours later.

 

[DonW]

You mentioned adding kent calcium. What are you using to raise alk? When your trying to keep a tank in check by adding powders, you can get alot of wierd fluctuations. This is easy to combat by doing good sized reagular scheduled water changes along with dosing. You will find that dissolving any powder in warm rodi will get more into the solution. You'll also find that its going to take alot of additive to keep up with a growing reef. 1/2 tsp per 50g is not going to make much difference in any tank, this is why ca reactors were invented. If you can find a more balanced way to keep up with demand your going to make your life much easier. Alot of people start out with kalk and two parts additives. The water changes are really what is going to help when your dosing ca and alk buffer.

Don

 

[Sk8r]

I'm using Kent buffer for the alk. I do weekly 10% water changes. I'm kind of looking at a Schuran reactor, and I've inquired about kalk, but am still using teaspoons until I really understand what I'm doing and what direction I ought to go. Calcium hydroxide vs calcium choride...interesting. Straight testtube chemistry was never my forte, but I'm remembering my basic chemistry much, much better lately...

Thank you all. This is getting interesting.

 

[DonW]

I'm using Kent buffer for the alk. I do weekly 10% water changes. I'm kind of looking at a Schuran reactor, and I've inquired about kalk, but am still using teaspoons until I really understand what I'm doing and what direction I ought to go. Calcium hydroxide vs calcium choride...interesting. Straight testtube chemistry was never my forte, but I'm remembering my basic chemistry much, much better lately...

Thank you all. This is getting interesting.

One nice thing about the ca hydroxide is that its balaced already. It can be a bit of a pain to mix up. As far as additives go using powder can get expensive unless you use substitutes. In your case Dri-z-air and baking soda would do just as good as the Kent at a fraction of the cost. Also I'd up the water changes to 20 or 30 percent balancing the salt mix. FYI the schuran pico would be perfect for your tank. Schuran reactors when set up properly are way under rated.

Don

 

[Sk8r]

Thanks for all the good advice---I've added up all the communications and I've done a little research into the Schuran unit, which would actually fit my stand (a real problem with a 52 corner). That might well be the way to go. And I'm going to do those water changes. At least everything in the tank is happy and hungry, and I want to keep it that way.