The PHZINC pH analyser is the result of 40 years of experience with design, construction, servicing and sale of pH analysers to zinc plants. The Norzink/Halland pH analysers have been sold to zinc plants world-wide for 40 years. The first model was developed at the Norzink zinc plant in Odda 1971. In the early 1980’s Norzink developed a new model, it was called “SLURpH” this model replaced the first generation and many zinc plants bought this analyser. In 1998 Norzink decided to focus on core business, zinc production, and the instrument business was handed over to Halland Instruments AS. In 1999 the third generation of PH analysers where developed, the model PH-13. These analysers where sold to several zinc plants. For instance Hindustan zinc bought many analysers for the three new zinc plants they build in 2004, 2006 and 2008. The experiences we got from commissioning and servicing these plants in Rajasthan in India, with ambient temperatures up to 50 degrees centigrade, were the reasons to develop a new analyser, the model PH-1300A. The analyser have been developed even further from the experience we got by commissioning and servicing of 20 analysers in the years 2010-2013 at the Boliden Odda plant and is today our main product, the PHZINC pH analyser.