Conductivity is used to monitor chemical concentration and control it by adjusting the ratio of water to acid or caustic. Chemical concentration control applications can be hard on conductivity sensors as high concentrations of acid or caustic can corrode the metal electrodes. In many concentration control applications, such as cleaning solutions, the acid or caustic solution is recycled back to the concentration control mixing tank for re-use. This can lead to the accumulation of solids in the solution that can coat or plug the electrodes on contacting conductivity sensors, resulting in an unreliable measurement. The Rosemount™ 228 Toroidal Conductivity Sensor is an excellent solution for most concentration control applications due to its superior corrosion and coating resistance compared to contacting conductivity sensors.