1. IC Controls Quality Water Solutions for pH www.iccontrols.com pH / ORP Conductivity Dissolved Oxygen Chlorine Standards R1.0 © 2004 IC CONTROLS Concerns in pH # 5: Caustic Ion Error CONTROLS

2. IC Controls Quality Water Solutions for pH www.iccontrols.com pH / ORP Conductivity Dissolved Oxygen Chlorine Standards R1.0 © 2004 IC CONTROLS PROBLEM As pH increases the concentration of hydrogen Ion (H+) decreases. As the hydrogen ion concentration decreases the glass will start to recognize Sodium as Hydrogen, thus giving false low pH readings as seen in the graph on the following slide.

3. IC Controls Quality Water Solutions for pH www.iccontrols.com pH / ORP Conductivity Dissolved Oxygen Chlorine Standards R1.0 © 2004 IC CONTROLS High pH Effect On Different Types of Glass

4. IC Controls Quality Water Solutions for pH www.iccontrols.com pH / ORP Conductivity Dissolved Oxygen Chlorine Standards R1.0 © 2004 IC CONTROLS Cause At High pH Hydrogen Ion Concentration is low and Sodium Levels are high. Sodium (Na + )looks like Hydrogen (H + )to the glass at levels above pH 10. At pH 10: H+ Concentration is 10 -10 Na+ Concentration is 10 -4 OH- Concentration is 10 -4 Thus the concentration of Sodium and Hydroxide is one million times greater.

5. IC Controls Quality Water Solutions for pH www.iccontrols.com pH / ORP Conductivity Dissolved Oxygen Chlorine Standards R1.0 © 2004 IC CONTROLS As the pH increases the concentration of Hydroxide (OH - ) increases. The increased concentration of Hydroxide (OH - ) will etch and dehydrate the surface of the glass causing sluggish response. Caustic Etching

6. IC Controls Quality Water Solutions for pH www.iccontrols.com pH / ORP Conductivity Dissolved Oxygen Chlorine Standards R1.0 © 2004 IC CONTROLS In Applications Normally Above pH 10 use High pH glass Wash the sensor in Muriatic Acid If sensor becomes very sluggish use Renew Solution to replenish glass surface High pH glass improves response time and longevity Proven Technology Superior Design Better Results Solution