chemistry 101

[cathy]

Over the weekend my LFS checked my water for me, and told me
that my calcium levels were a little low. (360)
They recommended the addition of Calcium chloride in a gradual manner. (Ie, 1/8 tsp granules per 50 gal, dissolved in water, added once per day til the calcium is up to 400)
I asked about Kalkwasser as a means to bring up the calcium.
In their opinion, they thought the CaCl2 would do a better job for my purpose. They did recommend using Kalkwasser though, in a very dilute solution which you let stand and precipitate first; this water then used as topoff water. They said this would help CO2 buildup. Can anyone explain this - how that would work?
Also, I read in one of my books that if you use CaCl2, you want to use it in conjunction with a buffer. I am assuming that this is to keep the dKh at a good level. Is my assumption correct - can anyone clarify or explain in detail?

[Boogiechillin]

Good questions with really long answers. I wound up copying an explanation of this interaction to a webpage to avoid constantly re-writing them:

http://filebox.vt.edu/users/jdahling/bigthree.htm

HTH,
BC

[cathy]

This site was very helpful about clarifying what happens between pH, dKh, and Ca. Also helpful to know that if you can't increase your calcium levels w/o lowering your alkalinity, its probably better to keep the alkalinity high! Right now my alkalinity is just where it should be, as is my ph. I will continue to watch all three parameters as I try to tweak my Calcium upwards....

Good info on the Kalkwasser too; I did not see any mention of the use of Calcium chloride. Anybody have any info on this?

[OrionGirl]

I am way not the chemistry guru, but I follow their advice. Here's some good info on calcium chloride use: http://www.animalnetwork.com/fish2/aqfm/1998/dec/bio/default.asp

[cathy]

thank you for your reply too! looks like a good site to explore...

[Boogiechillin]

Cathy, calcium chloride is what you typically get when you buy a calcium supplement to manually dose. When it hits the water, the chloride breaks away as it has a stronger affinity for sodium ions in the water, leaving Ca++ ions in the water for uptake by corals. Just substitute calcium chloride in when I talked about Ca++ on my webpage.

[VoodooChild]

Boogie, that's a good site. Very simple and easy to understand (if only I knew math). I was wondering if I could print out a few copies and distribute them at the Petco I work at. We're getting saltwater next month and I think we're in a good position to provide some of the better aquatic service in the area (I know, big claim for a chain LFS:) ) but it's good stuff and it could only help my co-workers learn. Just asking for permission.

[cathy]

thanks, all, for the replies. Here's some chemistry in action. See what you think. since last Saturday, I have been adding carefully adding measured doses of Ca Cl2 to my tank. Checking calcium daily. It slowly rose to 380 from 360. In the same time period, my pH went from 8.2 to 8.3, and my dKh went from 10 drops to 9 drops. (if you want I'll get the package insert out and convert that to actual values; the desired target is 10 drops). Any comments on these observations? I didn't add anything today, decided just to recheck tomorrow.
PS all residents happy and healthy in the meantime.

[Boogiechillin]

If I'm understanding the dkh drop procedure correctly, this would indicate that your alkalinity is lower, correct? This likely the result of dosing the calcium, which is combining with carbonate (the buffer) and lowering overall alk readings.

This is just my experience, but you're not going to get calcium much above 370-390 ppm with manual dosing - you're losing too much as calcium carbonate, and you can't dose enough to justify the cost. Understand that these aren't bad calcium levels by any means; in fact, unless you've got a tank full of tridachnid clams or stony corals, this is plenty. But, if you want to get calcium much higher, I would start saving for the reactor rather than dumping money into supplements with no payoff.

[cathy]

thanks for the advice. I think I am just going to aim to maintain my parameters about where they are! If it ain't broken......

[Ray Pollett]

I prefer to do water changes to cure this imbalance. I personally am not a big fan of adding the chemicals to try and balance the three pH, Cal and AlK. Doing water changes will bring these into correct balance and is the best way to avoid possible problems IMO.

Ray

[mogurnda]

I prefer to do water changes to cure this imbalance. Which salt mix are you using? Instant Ocean's Ca is 350, so there's no way to get Ca above this without supplementation. I am not a big fan of additives, but my dosing schedule with B-Ionic keeps the Ca at about 425 with an alkalinity of 3.5. Is this necessary? I can't say. Borneman's and Sprung/Delbeek's books say that Ca >400 is desirable for coral growth, so that's what I do.

[cathy]

what an interesting and helpful discussion! thanks all.

Ray, good point about water changes. When my water was tested last week, (when the calcium was 360) I had done a water change 24 hours earlier. I had intended to only do a 10%, but I was using a new vacuum/siphon gizmo that attaches to the faucet, and it ended up being about 20%....

Dave, we have been using Reef Crystals for our salt mix. I am going to have to look up the calcium percentages, am also curious about magnesium. If anyone else is familiar with this product, please chime in!
Can you tell me about B-Ionic? Is calcium chloride the chief ingredient? Does it contain other supplements like Mg?

[mogurnda]

Hi Cathy,

Reef Crystals has higher Ca (not sure exactly how high), so you might actually be able to get by with just water changes like Ray suggests. I have never worried about Mg, because it isn't consumed in the same quantities as Ca, and I have never had any indication that it's low. Water changes should keep Mg at a decent level.

ESV B-Ionic is a two-part supplement. One Part is CaCl2, the other NaHCO3. You get balanced Ca and alkalinity that way. You could actually make your own, but I am too lazy and it doesn't cost that much for a 20 gallon tank. It does contain trace elements, which I don't tend to worry that much about because I do regular water changes. It was helpful to have the Ca and alk separate in the beginning, because it allowed me to correct an imbalance of too high alk too low Ca. Now I have a regular daily dosing schedule that keeps everything constant.

In case you need more confusion, I mean information, this article (http://www.advancedaquarist.com/issues/feb2003/chem.htm) really helped me understand what was happening with Ca and CO3.

[BrianH]

Cathy,

A lot of reefers who keep SPS, LPS or clams use kalk in their top off water to maintain calcium and pH. It is difficult to raise your Ca using kalk. It is really better suited to maintain the Ca levels if you keeping critters who use up the Ca in your tank.

Brian.

[cathy]

really good article..............now I understand what my LFS was talking about in regards to Kalkwasser and Co2.

also, I can see why my salinity showed a nudge upward this morning!

I had used a buffer a couple of weeks ago to raise the alkalinity; then last week started gradually added the CaCl2....did I inadvertently simulate to some extent the reaction described?

I will continue to watch to see what happens, see what I can do with what I've already purchased...if that doesn't work you've given me another alternative to consider, not to mention a better grip on what could be going on!!

[Ray Pollett]

I use Kent Sea Salt.

Ray

[Ray Pollett]

Here is an interesting post:

http://216.168.47.67/cis-fishnet/JAAS/Jaas_8_2.pdf

Ray