Testing lime water

[SPC]

Hi Randy, we were discussing on the main board how we test the kalk water leaving our Nilsen reactors. I have always tested mine using my PH meter but another poster posted this:
The best way to test the potency of limewater is to use a conductivity or salinity meter. Saturated limewater will have conductivity of about 10.5 mSv (I am going from memory, but I think that is close). The trouble with pH is that a little lime will increase the pH quite a bit. The pH will be near maximum even when the lime is still far from saturated since it is not a linear relationship. The conductivity will be linear (assuming pure Ca (OH)2). So a conductivity of 5 means the lime water is only 1/2 saturated.

What is your opinion on this matter, I hate to think I have to buy another meter now :lol: .
Steve

 

[randy holmes-farley]

I agree with the post that a conductivity meter is a great way to measure saturation of limewater. I've been doing that for many years. It does need to be accurate around 9-11 mS/cm.

pH is a poor choice, but it can be done. What you want to do via pH is compare the water to known saturated limewater (put a few spoonfuls of lime in a cup of water and let it sit a while to fully saturate. Then compare the pH to the reactor output. A drop of 0.3 units means roughly a drop by 50% in the concentration.

You can also simply measure the calcium or alkalinity of the limewater coming from the reactor using a test kit.

 

[SPC]

Thanks Randy.
Steve