Under control: electronic controllers measure sanitizer levels in several ways. This guide can help you pick the right one for the right pool.

Electronic controllers are becoming more and more prevalent. Their ability to continuously monitor and maintain water conditions makes them popular with health departments, facility managers and municipal organizations.

Lots of effective controllers are available now, and many use different systems to measure sanitization in pools. The three most popular methods are colormetric ppm, ORP and amperometric ppm. Understanding the basis of each measurement can assist operators in managing their pools.

Colormetric

Colormetric ppm measures sanitizer levels in parts per million, but it takes its measurements in a different way.

The term "colormetric" is used to describe a system of measurement where reaction-based indicators (reagents) are used to detect the presence of a specified chemical, such as chlorine. The indicator reacts with the specified chemical and produces a visible color change in the solution. The stronger the color of the solution, the more compound is present.

DPD test kits, an example of a color metric measuring device, are familiar to those in the aquatics industry. However, studies have shown that there can be significant differences in readings from these kits due to variations in color perception between individual users. When the "eye" that evaluates the test is automated, though, a DPD kit becomes an accurate measure.

So, essentially, a colormetric system is an automated DPD test kit. The controller is programmed to test the chemical levels in the water at certain times or intervals each day. When it's time to test, the controller will send a signal to a colormetric unit.