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topic 52466

What is Cation Conductivity

A discussion started in 2009 but continuing through 2019

June 22, 2009

Q. What exactly is Cation conductivity and how it is beneficial in boiler water?

Prasad Reddy
Researcher - INDIA

June 23, 2009

A. Hi, Prasad. Apparently cation conductivity is not just a property, but a technique:

"In high pressure steam systems, cation conductivity is a useful tool for monitoring return condensate for low levels of contamination by anions such as Cl-, SO4-, HCO3-, etc. In practice, a cooled sample of condensate or high purity water flows through a cation exchanger in the hydrogen form. The cation resin replaces contaminating cations such as Ca++, Mg++, Na+, NH4+, and amines in the sample with hydrogen ions. The hydrogen ions exchanged for the other cations in the sample increase the conductivity contributed by the contaminant salts of mineral acid anions listed above by 3 or 4 times. Thus the cation exchange column can be thought of as a "conductivity amplifier" for mineral and organic acid contaminants; increasing the sensitivity of the conductivity analyzer to low levels of contamination. "

-- per


Ted Mooney, Teds signature
Ted Mooney, P.E. - Pine Beach, New Jersey
Striving to live Aloha

Ed. note Nov. 2017: Sorry: Suez Water has purchased that domain and is apparently not maintaining the article because the link redirects to, which is in turn broken :-(
Update Jan. 2019: is now a broken domain; there is now a technical library at, but 'cation conductivity' is not found in it. You can however still see the article at

February 13, 2015

Q. The cationic conductivity was well defined.

I would like to clarify --
1. Will Cationic conductivity of live steam be higher than that of the condensate return from the turbine, or both will be same?
2. Is there will be effect of cooling system for steam condensing after exhaust from steam turbine, i.e., air cooled system or water cooled system will have any effect?
3. Is there any Feedwater limit to achieve cationic conductivity < 0.3us/cm?


Nisar Ahmad
- Rawalpindi, Pakistan

A. Hi Nisar. This is not a subject within my experience, but ...
1. Based on the paragraph I just quoted, it seems that the cation conductivity techniques can only be applied on "a cooled sample", so the question is actually inapplicable. 2. If any operation introduces contaminants, it will increase conductivity; if not, it won't. 3. Certainly if you want very low conductivity the feedwater must be of very low conductivity; surely as low, and probably lower, than the conductivity you desire in the condensate.


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Ted Mooney, P.E. RET - Pine Beach, New Jersey
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January 11, 2016

Q. When a sample stream is passed through a specific conductivity meter and then through a cation conductivity meter, which one should read higher? Why?

tom Mattingly
- whitesville, Kentucky, usa

January 2016

? Hi Tom. Which one IS reading higher please Tom? :-)

Please try to explain your actual situation for us :-)

Thanks for your understanding.


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Ted Mooney, P.E. - Pine Beach, New Jersey
Striving to live Aloha

January 24, 2016

Q. I work at a power plant and although others and myself monitor cation conductivity, I'm not sure any of us understand it.

Question: a sample stream passes over a specific conductivity meter then through a cation resin column and the cation conductivity meter. Which meter should have a higher reading, the specific or the cation?
What does cation conductivity measure?

tom mattingly [returning]
tech - whitesville, Kentucky

Hi Tom. Again, please tell us which of the two meters has been reading the higher conductivity.

Although I'm not actually acquainted with this stuff, my understanding based on the paragraph I quoted is that the cation conductivity meter should read higher. It sounds like:
- if the amount of contaminating chlorides, sulfates, and carbonates is reasonably low, the water will not be very conductive, and therefore it's hard to monitor and watch for those chloride, sulfate, and carbonates anions of concern. But if you pass the water through a cation exchanger first, thus replacing the less conductive Ca++, Mg++, Na+, NH4+ cations in the water with hydrogen ions (which are highly conductive), it will render the contaminated water 3 or 4 times more conductive and thus it is easier to monitor for the presence of those troublesome anions.


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Ted Mooney, P.E. RET - Pine Beach, New Jersey
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November 24, 2016

A. Hi Tom, the specific conductivity meter shows a higher reading than the Cation meter, because the specific conductivity meter is showing total reading of cation+anion but the cation conductivity meter only gives the reading of cation.

Muhammad Saqib
- Islamabad Pakistan

May 10, 2017

A. But if you have contamination of amines in that water, then specific conductivity will show it, and cation conductivity won't. Therefore specific conductivity probably will be higher. You can read about it here:

"Cation (acid) conductivity is the technique of continuously conditioning the sample by passing it through a hydrogen form cation exchange cartridge. It enhances the sensitivity to contaminants by two means:
-- Ammonia or amines that are intentionally present at ppm levels are removed. This eliminates their high conductivity. The lower ppb concentrations and conductivity of contaminants can then be "seen" by the measurement.
-- Contaminant corrosive salts are converted to their respective acids which are typically three times as conductive as the original salt because of the highly conductive hydrogen ion."

Dmytro Tarianyk
- Cracow, Poland

thumbs up sign Hi Dmytro. Thanks for the excellent reply and the link to a great article!

But now we have two responders saying it will be higher and one saying it will be lower, each offering a beautiful theory ... but still no actual data from the OP despite two requests ... and Richard Feynman rolling over in his grave :-)


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Ted Mooney, P.E. RET - Pine Beach, New Jersey
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How to reduce steam conductivity?

July 7, 2017

Q. Our steam pressure and temperature are 147 barg and 540 °C. Steam cationic conductivity is in the range of 0.3-0.6 µS/cm. This steam is also supplied to our client and they are asking for <0.1 µS/cm. Is it possible to achieve? If yes, how? Thanks.

Jo Jayakumar
- Chennai, Tamilnadu, India

November 22, 2017

Q. What is the difference between Cation Conductivity & Electrical Conductivity in Water samples?

Waqar Khan
National Refinery Limited - Karachi, Sind, Pakistan

November 2017

A. Hi cousin Wagar. Cation conductivity is a technique as well as a measurement. Before measurement, the water is passed through a cation exchanger which both removes amines and increases the sensitivity to anion presence by replacing the Calcium, Magnesium, and Sodium cations with hydrogen ... which makes the water 3 to 4 times more conductive.

If careful study of this page doesn't clarify it for you, please phrase your question like: "I understand that blah, blah ... but what I am not understanding is blah, blah ..." so we can see where the difficulty lies. Good luck.


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Ted Mooney, P.E. RET - Pine Beach, New Jersey
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March 4, 2018

Q. Though here it has been mentioned that cation conductivity will remove the effect of ammonia contamination, in practice here when high feed of ammonia it increases cation conductivity. Why that observation? Apart from cation column hasbeen placed a degasser as well. But this observation can see. This increase is done by ammonia ions or by contaminants in the ammonia solution?

Geethani Weerskon
- Colombo, Sri Lanka

February 1, 2019

Q. Please tell us what is the procedure for measuring whether a cat sensor is healthy or unhealthy?

Palash Maity
Powermech projects ltd. - Tamluk, West bengal, India

February 2019

A. Hi Palash. As site curator, but not an expert in cation conductivity, I would suggest that pending better answers you could return the sensor to the manufacturer for calibration, or do a majority rule with a test of three sensors, or maintain some test solutions of known conductivity. Sorry, that's all I've got :-(

As I've said previously on this page, when questions are posted in abstract fashion they are lifeless and never offer enough facts to enable an answer without numerous "ifs, and, & buts", so you lose the majority of people who could probably help you -- whereas the actual situations people find themselves in are usually quite interesting and specific.


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Ted Mooney, P.E. RET - Pine Beach, New Jersey
Aloha -- an idea worth spreading

August 12, 2019

Q. Minerals exchanged with Hydrogens ions will have 3 times higher conductivity? So basically cation conductivity will have higher value than standard conductivity? I am missing something here?

Destyawan Anwar
- Jakarta, Indonesia

August 2019

thumbs up sign  I think you've got it, Destyawan.


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Ted Mooney, P.E. RET - Pine Beach, New Jersey
Aloha -- an idea worth spreading

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