Is there a correlation between conductivity and temperature?

[Willz]

I'm seeing these two fluctuate in a very similar pattern and just wanted to know if these readings are correlated on APEX (or in general)?

 

[redfishbluefish]

Shhhhhh....don't tell anyone. I don't own an Apex, but I'm willing to bet my antique ReefKeeper II that the conductivity reading is coming from the pH probe (aka conductivity probe).

 

[Willz]

Shhhhhh....don't tell anyone. I don't own an Apex, but I'm willing to bet my antique ReefKeeper II that the conductivity reading is coming from the pH probe (aka conductivity probe).

It has both a pH and a conductivity probe. I have all four that come with the new Apex (temp, pH, conductivity, and ORP). Why would they send a separate sensor if the pH does both? I mean, if that is the case then I'll never have to calibrate or replace the conductivity probe again, which I would like!

 

[redfishbluefish]

Now you have me scratching my head. I thought conductivity was determined, and then using a special equation, you calculate pH.

Here are the definitions off the net:

pH probes measure pH by measuring the voltage or potential difference of the solution in which it is dipped. By measuring potential difference, hydrogen ion concentration can be calculated using the Nernst equation which gives the relationship between Hydrogen ion concentration and Voltage or Potential.

A conductivity meter measures the amount of electrical charge an aqueous solution can carry. The conductivity meter uses a probe to measure conductivity of a solution. ... Depending on the concentration of ions in the solution, the conductance is either high or low, which results in a fast or slow current reading.


HERE's your answer.

 

[clowner]

Well the hotter it is the more salt could be dissolved therefore raising conductivity

 

[dragon99]

Yes, the conductivity of saltwater increases as temp increases.
http://www.comsistel.com/HAM documents/seawater.pdf

The salinity isn't changing, but the conductivity is.

 

[Willz]

Now you have me scratching my head. I thought conductivity was determined, and then using a special equation, you calculate pH.

Here are the definitions off the net:

pH probes measure pH by measuring the voltage or potential difference of the solution in which it is dipped. By measuring potential difference, hydrogen ion concentration can be calculated using the Nernst equation which gives the relationship between Hydrogen ion concentration and Voltage or Potential.

A conductivity meter measures the amount of electrical charge an aqueous solution can carry. The conductivity meter uses a probe to measure conductivity of a solution. ... Depending on the concentration of ions in the solution, the conductance is either high or low, which results in a fast or slow current reading.


HERE's your answer.

Thanks! That answer is for correlation between conductivity and pH. I was hoping to know whether the temperature and conductivity measurements could be correlated.

 

[Willz]

Yes, the conductivity of saltwater increases as temp increases.
http://www.comsistel.com/HAM documents/seawater.pdf

The salinity isn't changing, but the conductivity is.

Thanks! That's why I was trying to use "conductivity" instead of "salinity". So, temperature may be a factor in why it fluctuates throughout the day.

 

[Willz]

Here is what I found online that speaks to it, but I don't understand it enough to make a good interpretation:

http://www.reagecon.com/pdf/technicalpapers/Effect_of_Temperature_TSP-07_Issue3.pdf