Measuring water Conductivity

Recently I designed a conductivity sensor that I interfaced with arduino. At first I incountered ac noise problems and filtered them successfully. Second challenge is ,my sensor puts out 0-2vdc with 1% accuracy (0-2000micro/S) however i want to bump it up to 0-5vdc(0-2000micro/S).The only solution is to change the range to 0-5000micro/S to get 1vdc per 1000 micro/S but accuracy drops to 10%.

Thank You. I used duemilanove's 3.3 vdc with voltage divider brought it down to 2vdc as external analog reff.Works Great!!!

Recently I designed a conductivity sensor that I interfaced with arduino.

Can you tell us more about that sensor?
How does it work? Range?
For sale?

Sensor is a potentiometric type two carbon electrodes with .k1 constant capable of measuring ultra low to high conductivity of the water.
circuitry and electrode are combined all in one making it a plug and play module without the high cost. Simply connect water inlet /outlet fittings to circulating water line .Electrical conections done through 3 wire din connector (+,ground,signal).
Range can be from 0-5000micro/S. Output voltage 0-5vdc.For more information check the site or ebay.

http://webpages.charter.net/tdsmeter/conductivity.html

http://cgi.ebay.com/Arduino-sensor-/130530484441?_trksid=p5197.m7&_trkparms=algo%3DLVI%26itu%3DUCI%26otn%3D4%26po%3DLVI%26ps%3D63%26clkid%3D503776948148153454