Medway 2 Buffer The Medway 2 Buffer System is available for installations where either the pH of the water sample needs to be lowered or where measurement of combined or total chlorine residual is required. The buffer system consists of a precision peristaltic pump and a portable container for the buffer solution. The buffer solution is accurately dosed directly into the measuring cell.

	Long life tube element
	Low maintenance
	Increased accuracy and stability
	Drip rate indicator
	24 v AC operation (from the Medway 2)
	Peristaltic pump

How It Works

Residual chlorine in treated water has two major components, hypochlorous acid (HOCl) and hypochlorite ions (OCl). The quantity of each component in the sample is dependant upon the pH value of the water, the component of interest is the content of HOCl. At a pH of between 4 – 5 the free chlorine is nearly 100 % HOCl, whereas at a pH level of 10 – 11 the free chlorine is nearly 100 % OCl.

It is recommended that a buffer system is used when the water sample needs to be stabilised. This enables the monitor to accurately measure the HOCl content at a lower pH level and ensuring repeatable accuracy.

The Medway 2 buffer system can use either phosphate or acetic acid solutions. To measure total chlorine, potassium iodide is be added to the buffer solution. The Medway 2 also has the option for carbon dioxide (CO₂), buffer addition.