Pyxis Lab

Inline Flourometer


ST-500 series probes are UV excited inline fluorometers used for measuring the concentration of PTSA in cooling tower and RO water systems. It measures traced chemical residue every 4 seconds in the sample water with 2% accuracy. It allows an optimal narrow band control in the treatment chemical concentration for cost effectiveness and, more importantly, best treatment performance.
Turbidity and color in most cooling tower applications interfere traditional fluorimeters and lead to significant dosing errors, even up to 50%. With the ST 500’s proprietary optical design and sophisticated compensation algorithm, the ST 500 delivers great precision and accuracy for waters containing up to 150 NTU turbidity and 4 ppm iron. This breakthrough technology ensures ST 500 to outperform in the toughest cooling water applications while keeping maintenance demand at a minimum with our uPyxis diagnostics capabilities.


  • High resistance to color and turbidity interference from sample water
  • High temperature tolerant and high humidity resistant optical filter
  • Highly stable and extremely reliable even in harsh applications
  • Digital communication via Bluetooth to smart phone app for diagnosis and troubleshooting

Downloadable Files

2021 Pyxis Product Catalog2021 Pyxis Product Catalog
ST-500 Operation ManualST-500 Operation Manual
ST-500 Spec SheetST-500 Spec Sheet