Can I lower my calcium?

[JeremyGlen]

I am interested to find out if I can lower my calcium without lowering my salinity.

I just got a brand new Hagen Master test kit and tested my water for a few different things. Everything looked great except my calcium. It read somewhere between 750 and 800. I knid of suspect that is why I am not getting any growth from my corals, or very little at all.

I just tested my RO water (<20), a batch of Oceanic that I have been phasing out(600-650@1.020sg), and a batch of my new Tropic Marin Pro Reef(400-500@1.0225sg).

I can do a water change, probable 5 or 10g, and lower it a little using just the TM, but I would like to know if there is any way of getting it down lower. I only have a total of around 32g water volume in my tank, equipment, and sump. I hope someone has an idea or a place to look.

[hobogato]

gary is probably the best person to ask about this with his chemistry background, but you may be able to increase your alkalinity slowly which should lower your calcium. i may be completely wrong about this tho - you should send him a PM.

[matt]

Unless your carbonate hardness (alkalinity) is very low, I suspect your calcium really isn't at 750 ppm. Hagen test kits are not known for their accuracy. Try this; see if you can borrow or buy a salifert Ca kit and a salifert Alk kit, and re test your water. If the alk is very low and the Ca is very high, add some buffer. If your ph is okay you can use baking soda or just buy some buffer. Keep adding it, maybe a tablespoon dissolved in RO water every day, until your alk is around 3.0-3.5 meq, or dkh at 7-10. You might get a "snowstorm" meaning Ca could precipitate out if it is really that high. Then check your Ca with the salifert kit, and see it says. I've never used Oceanic salt but I've heard it's high in Ca. If your alk is high enough but your Ca is still too high I don't know what to tell you other than I would suspect the test kit.

[NaCl_H2O]

Gotta agree with Matt, 750-800ppm Ca isn't very likely unless your hardness (dKH) is VERY low, and even then, I think 600ppm, maybe 650 is as high as you could get it? Gary is the one to verify??

I used Oceanic salt for a long time, and Ca never got much above 500 with dKH at 8-10

[hobogato]

my calc ran above 700 on and my alkalinty was very low when i used oceanic salt - that is why i now use IO.

[GaryP]

It is possible to get high calcium if you are using Oceanic salt in a tank with low calcium demand. I agree that you probably need to verify it with a more accurate kit. Either a Salifert or Seachem kit would be good.

If your coral is not growing I doubt that its because your calcium is to high, but rather that your alkalinity is to low. It takes both to get growth. Calcium and alkalinity needs to be balanced. Unfortunately when calcium gets to high, it causes the alkalinity to fall to low levels.

Besides doing water changes you can get the levels down by adding buffer. What you are doing is causing the calcium to precipitate out of solution as calcium carbonate. If you do this, you will need to pull your pumps out and clean them with vinegar. Precipitation occurs first in the pumps and it'll cause them to seize up, especially when are they shut off. Make sure to take the shaft out of the impeller when you soak them. Small granules of calcium carbonate scale on the shaft is all it takes to cause the pump to seize up. The pumps can burn up when they seize up like this.

There is another big issue here. If your alkalinity is low, chances are that your pH is pretty low too. Alkalinity and pH are definitely linked. Please let me know if there is anything else I can to help.

[JeremyGlen]

Well, I tested the alk and the ph and both were just right. The KH test measures in mg/l and is suppose to be between 105 and 125, mine was about 115. Th pH is right at 8.3. I guess I will try and get one of the salifert kits and try to test the Ca and dKH to see what it says. I have always had a problem with high Ca in my tanks.

[JeremyGlen]

I have been using some Kent buffer.

[matt]

I don't know what alk scale you're referring to (105-125) but the ones I'm familiar with are meq/l, which should be in the 3.0 area, and dkh, which should be 7-10. Sorry to harp on the test kit, but I really think it's worth it to get ahold of another kit and try to verify what you've got. There's an old advanced aquarist article by Randy Holmes-Farley (I think that's his name) called "solving problems with Ca and Alk" or something liike that. Check it out if you haven't already; it's a good explanation of common issues with Ca and Alk.

[GaryP]

Matt,

He is talking about the ppm scale. Seawater has an alkalinity of about 2.5 meq/L = 7 dKH = 125 ppm CaCO3 equivalents. Some of the off the wall kits give results in ppm.

[gjuarez]

The fact that a brand new batch of saltwater with oceanic tested at 650-700 leads me to believe that the test kit you are using is inacurrate. Oceanic is known for having high calcium levels, but not that high. ALso, you tested the batch at 1.20 sg which should give even lower levels of calcium. I am going to say that its probably the test kit. Borrow or buy a salifert test kit and try it on a new batch of saltwater. If you report the same results at 1.20 specific gravity with the salifert kit then there it is probably anohter bad batch of oceanic.

[JeremyGlen]

If the test kit is really that far off, I think I am going to call the company. It is brand new and those were the first tests I've done with any of it.

Sure do wish we had a decent store here in SM that actually carried stuff reefers need.

[gjuarez]

Why not take it to a lfs and have them test it for you. You can also take your test kit and maybe run a sample on theirs. Just a suggestion

[gjuarez]

Why not take it to a lfs and have them test it for you. You can also take your test kit and maybe run a sample on theirs. Just a suggestion

[JeremyGlen]

I have to drive at least 30 min or more to get to any LFS that might actually have a calcium test kit. I guess I can try if I find the time tomorrow.

[kkutac001]

Matt mentioned Farley. Here are some links to his articles (addressing Ca, Alk, pH, etc.) that I gather here for possible use by others.
[all articles by RANDY HOLMES-FARLEY]
http://www.advancedaquarist.com/issues/mar2002/chem.htm
http://www.advancedaquarist.com/issues/feb2002/chemistry.htm
http://www.advancedaquarist.com/issues/feb2003/chem.htm
http://www.reefkeeping.com/issues/2002-04/rhf/feature/index.php
http://www.advancedaquarist.com/issues/may2002/chem.htm