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AcroSteve
10/05/2006, 03:46 AM
Randy,

I was wondering if there was some sort of test, scientific or not, that would determine whether or not a solution of kalk was saturated.

Or is PH the only good guage?

Randy Holmes-Farley
10/05/2006, 04:50 AM
Conductivity is a far better gauge. Saturation is about 10.3 mS/cm. I show that here:

The Degradation of Limewater (Kalkwasser) in Air
http://www.reefkeeping.com/issues/2003-05/rhf/feature/index.php

pH can be used,but is crude. With pH, I'd always compare to a true saturated solution (say 2 teaspoons in a cup of RO/DI water) and look just at the pH difference. A difference of 0.3 pH units is a factor of 2 in potency.

kwgozy
10/05/2006, 08:37 AM
<a href=showthread.php?s=&postid=8280074#post8280074 target=_blank>Originally posted</a> by Randy Holmes-Farley
Conductivity is a far better gauge. Saturation is about 10.3 mS/cm.

How do you check the Conductivity? Is there a test kit or is it an electronic tester. Also what does 10.3mS/cm mean.

Also can anyone give me a good site or sites where I can get the meanings of these abbrevations ppm, mS/cm ect. Also a site with a periodic table and list of all the chemical elements and abbrev.

Thanks Kyle

AcroSteve
10/05/2006, 10:09 AM
How about a DIY conductivity meter?

http://www.reefcentral.com/forums/showthread.php?s=&threadid=931044&highlight=diy+conductivity+meter

I might look into this.

Randy Holmes-Farley
10/05/2006, 10:24 AM
I do not believe that you can make an accurate DIY conductivity meter. The nature of the probe is much more complicated than a simple metal.

I describe the process a bit here:

Using Conductivity to Measure Salinity
http://www.aquariumfish.com/aquariumfish/detail.aspx?aid=1804


Many companies sell then. For example, Pinpoint:

http://www.americanmarineusa.com/salinityfacts.html

Just make sure it has the right range. Many meters cannot read that high if they are primarily for monitoring purity of fresh water (like a TDS meter).

AcroSteve
10/05/2006, 10:47 AM
Thanks for the help Randy.

Do conductivity probes need replaced as often as something like a PH probe?

Randy Holmes-Farley
10/05/2006, 10:56 AM
They are not usually left in the water, and are quite rugged for normal uses, so can last a long time.

AcroSteve
10/05/2006, 03:05 PM
Great.

AcroSteve
10/05/2006, 04:59 PM
<a href=showthread.php?s=&postid=8280074#post8280074 target=_blank>Originally posted</a> by Randy Holmes-Farley
Conductivity is a far better gauge. Saturation is about 10.3 mS/cm. I show that here:

So, converted to uS/cm, would be 1,030?

And, if you would please, give your thoughts on a $47 handheld Milwaukee, or a $120 pinpoint.

Thanks again.

Randy Holmes-Farley
10/05/2006, 05:52 PM
10,300. :)

Do you have a link to the Milwaukee?

AcroSteve
10/05/2006, 06:04 PM
Sort of.
http://www.spectrapure.com/St_quality_p1.htm



I did some more searching, and this one caught my eye.
http://www.extech.com/instrument/products/alpha/EC400Lab.html

However, they sell a replacement "conductivity cell", so it may not last very long. The pinpoint says it should last a "lifetime"

Randy Holmes-Farley
10/06/2006, 04:57 AM
The Spectrapure ones have their range too low. The Extech one is Ok for limewater, but cannot read salinity of tank water. The Pinpoint will do both, but not pure fresh water.The

AcroSteve
10/06/2006, 10:14 AM
There are compromises everywhere, I guess.

Thanks for checking them out.

Randy Holmes-Farley
10/06/2006, 11:47 AM
:thumbsup:

There are compromises everywhere, I guess.

Yes, the ones that do everything cost a lot more.

Happy Reefing. :)