Portable Photometer for Calcium hardness with CAL Check standards

The HI97720C calcium hardness photometer is a dedicated portable photometer for measuring calcium hardness from 0,00 to 2,70 mg/L (as CaCO3) at 0,01 mg/L resolution. Within the HI97xxx series it employs a dust-, dirt- and water-sealed optical system with LED source, narrow-band interference filter at 525 nm and silicon photocell detection for accurate, repeatable readings. Accuracy at 25 °C is ±0,11 mg/L ±5 % of the reading, based on a calmagite method adapted from Standard Methods for the Examination of Water and Wastewater, 23rd Edition. Dissolved calcium and magnesium carbonates determine water hardness expressed as CaCO3 or MgCO3; their sum is total hardness. Hardness drives scaling of pipes, boilers and washers and can contribute to corrosion in heating, cooling, reverse-osmosis and demineralisation plant. CAL Check™ and NIST-traceable standards let users verify performance and recalibrate when needed; the built-in tutorial covers sample preparation and reagent quantities. Further functions include GLP calibration date/time recall, automatic storage of the last 50 results, reaction timer, battery-level display, auto-off after inactivity, IP67 protection and a backlit 128 × 64 monochrome LCD. The kit from manufacturer Hanna Instruments arrives in a transport case with two capped cuvettes, plastic inserts, CAL Check™ standards, scissors, cleaning cloth, three 1,5 V AA batteries, quality certificate and manual; reagents are supplied separately.

This article is part of Photometers & spectrophotometers, in Spectroscopy & photometry.

Key features

• Pack size: 1 pc
• Measuring range: 0,00–2,70 mg/L (as CaCO3)
• Resolution: 0,01 mg/L
• Accuracy (25 °C): ±0,11 mg/L ±5 % of reading
• Wavelength: 525 nm (LED)
• Method: calmagite (adapted from Standard Methods, 23rd Ed.)