Ca monitors: worth it?

[Steve G]

I'm sick of testing for Calcium and find that I can't seem to keep the Ca, KH, Mg parameters where I want them. Is a Ca monitor worth the expense? Does anybody have advice on selecting or purchasing them?

 

Thanks.

[davjbeas]

I have the pinpoint model of digital calcium monitor.

When I set it up the first time, i kept getting error messages when calibrating.

I called technical support and the sent me a new probe which was sealed and didn't

need to be filled with reference solution. Then it worked fine. however, this instrument

is not designed to read continuosly. they suggest get the reading and then store away the probe dry

after use. it has an accuracy of abot +-20ppm i would say.

It is easier than a test kit and runs on 9v battery.

it will cost you about $249.00

I don't know of any other maker currently selling a CA meter.

 

David B.

[dhoch]

You don't need to test but once a day at most frequent, and many do it less.

 

If you are haveing troubles keeping levels consistant... getting a monitor is not going to helpyou.

 

You need to figure out why the levels are not consistant.

 

Dave

[gastone]

I don't have a calcium monitor, but IMO it is not worth the expense. Calcium and Alk exist in an exact 1:1 ratio of one meq/L Alk to 20 ppm Ca. So, after your tank has burned through a meager 20ppm calcium, your alk is way out of whack, while the 20 ppm drop in calcium is insignificant. It is much more important to test your alk regularly as opposed to your calcium. I just can't justify spending $250 for something that I will use once a month, when I could achieve the same thing using a salifert test kit that will last for 4 years. I'd never recoup the expense.

 

JMHO.

 

Garrett.

[dhoch]

Garrett,

 

Many of us test much more frequently than 1/month... I test pretty much every day (but for alk as you do)... I test salinity about 1-2 times per week, especially after water changes, I do Calcium, Magnesium once in a while, and nitrate if I think that might be rising (more algae growth).

 

Dave

[Steve G]

Thanks for the replies. I have a pH monitor and I love it. I like having data but I hate all the time of gatehring it. Was not sure if a Ca monitor would give me the same amount of utility, but I suspect at $250 it's not worth it.

[lmeyer]

Calcium and Alk exist in an exact 1:1 ratio of one meq/L Alk to 20 ppm Ca.

 

Not to hijack the thread, but...

 

I have read that there is a limit to how high you can push calcium and alkalinity simultaneously. Reading http://www.wetwebmedia.com/calcalkmar.htm indicates that if you try to push both too high you can get a "sudden precipitation of carbonates (the alkalinity falls/crashes)". I don't remember seeing an exact ratio like the one supplied. Can you steer me in the right direction?

 

Also, that ratio doesn't sound right to me. The same post lists the desired ranges for calcium and alkalinity that I am used to seeing, 350-450 ppm Ca and 8-12 dKH Alk. To convert dkH to meq/L , divide by 2.8. 12 dkH Alk = 4.2857142857143 meq/L. This would equal about 85 ppm Ca by the ratio listed. Am I missing something?

 

Back to the main point of the thread, the fact that the monitor can't be used continuously does it for me. I use the SeaChem calcium test and it is pretty easy to use and the color change is obvious. By the time I get out the probe (probably have to re-calibrate) take the reading, properly clean the probe, and put it away, I might as well just do my manual test. Add in the cost of the monitor (and probably replacement probe costs periodically) and its really not a hard choice for me.

[dhoch]

I have read that there is a limit to how high you can push calcium and alkalinity simultaneously. Reading http://www.wetwebmedia.com/calcalkmar.htm indicates that if you try to push both too high you can get a "sudden precipitation of carbonates (the alkalinity falls/crashes)". I don't remember seeing an exact ratio like the one supplied. Can you steer me in the right direction?

 

All that is correct... there is a relationship between alk and calcium, but it's not linear as alluded to above (See this article by randy: http://www.reefkeeping.com/issues/2002-04/...ature/index.php )

 

There is a table in that article...

 

Also there is a good online calculator for adding calcium and alkalnity suppliments that will calculate the relationship (but I haven't looked into the formulas behind it).

 

Dave

[johnnybv]

All that is correct... there is a relationship between alk and calcium, but it's not linear as alluded to above (See this article by randy: http://www.reefkeeping.com/issues/2002-04/...ature/index.php )

 

There is a table in that article...

 

Also there is a good online calculator for adding calcium and alkalnity suppliments that will calculate the relationship (but I haven't looked into the formulas behind it).

 

Dave

We have a pinpoint monitor running here at our shop on our coral system, you are welcome to come and check it out. The calibration is easy and quick, if you are testing multiple tanks it is worth the investment. If you are testing 1 tank, a salifert Ca test is easy and cost effective. The meters do sell for $249, I like it and think its worth the investment for multiple tanks, or for the Ca testing addicts that test daily.

John

[gastone]

Not to hijack the thread, but...

 

I have read that there is a limit to how high you can push calcium and alkalinity simultaneously. Reading http://www.wetwebmedia.com/calcalkmar.htm indicates that if you try to push both too high you can get a "sudden precipitation of carbonates (the alkalinity falls/crashes)". I don't remember seeing an exact ratio like the one supplied. Can you steer me in the right direction?

 

Also, that ratio doesn't sound right to me. The same post lists the desired ranges for calcium and alkalinity that I am used to seeing, 350-450 ppm Ca and 8-12 dKH Alk. To convert dkH to meq/L , divide by 2.8. 12 dkH Alk = 4.2857142857143 meq/L. This would equal about 85 ppm Ca by the ratio listed. Am I missing something?

 

Back to the main point of the thread, the fact that the monitor can't be used continuously does it for me. I use the SeaChem calcium test and it is pretty easy to use and the color change is obvious. By the time I get out the probe (probably have to re-calibrate) take the reading, properly clean the probe, and put it away, I might as well just do my manual test. Add in the cost of the monitor (and probably replacement probe costs periodically) and its really not a hard choice for me.

 

 

 

From one of the good doctors... I'm sure he's much better at this than I am. I suppose I meant to say that calcium and alk as calcium carbonate (usable by corals) exists in an exact one to one ratio.

 

Calcium and Alkalinity Demand: Calcium Carbonate Mathematics

 

Calcium carbonate formation consumes its two components in an exact 1:1 ratio. In the units used by aquarists, this ratio corresponds to one meq/L (2.8 dKH; 50 ppm CaCO3 equivalents) for every 20 ppm of calcium. Not surprisingly, this is also the ratio of alkalinity to calcium that is supplied when calcium carbonate is dissolved, as in a CaCO3/CO2 reactor. Fortuitously for the aquarist, this is also the ratio supplied when calcium hydroxide is dissolved, as with the use of limewater (kalkwasser).

 

 

You can read the entire article here: http://www.reefkeeping.com/issues/2004-12/rhf/index.php

 

 

Garrett.

[lmeyer]

From one of the good doctors... I'm sure he's much better at this than I am. I suppose I meant to say that calcium and alk as calcium carbonate (usable by corals) exists in an exact one to one ratio.

 

Thanks, that makes more sense. Also is shown in the link that Dave supplied.