View Full Version : testing salinity through resistance?

01/12/2008, 10:13 AM
I have access to a fieldpiece digital multimeter. Is it possible to test my salinity by the resistance? Ok well I know it is possible because it's an electrolyte solution and depending on the concentration of the ions in the solution (saltwater) the resistance will change so theoretically I know it is possible but I don't know how to go about it. Anybody have an idea?

01/12/2008, 10:20 AM
That is basically how a conductivity meter works with one diference, multimeters usually use direct current to make the measurement while good conductivity meters use alternating current. this is to prevent the battery effect that will very fast coat the electrodes falsifying the reading.
Get a good refractometer, cheaper, easier to calibrate and very practical to use and usually more reliable.

01/12/2008, 02:19 PM
This article might help:


01/12/2008, 02:39 PM
Thanks! that article was exactly what I needed to read. I'll just have to wait till I can afford a better refractometer. I have a crummy one that measures solids in percentages. I just calibrate it based on proper salinity and compare it to the water in my tank. Not elegant but it works kinda. I thought I might've had an easy, and precise method sitting in the other room waiting for me to unlock it's secrets.. but alas.. it was not meant to be.

Thanks though both of you guys!

01/12/2008, 03:24 PM
You're welcome!