Based on standard colorimetric methods, the CLpcx on-line phosphate analyser have been designed to reduce maintenance to a minimum ensuring a cost-effective ownership. It constitutes a perfect complement to the UVpcx nitrate and ammonia analysers based on UV spectroscopy for wastewater treatment plants. The high range model is ideally suited to monitor wastewater and industrial water containing phosphate additives like boiler of power plants. The low range model is more suited for drinking water, rivers and lakes, or even wastewater after a phosphate removal process.