Cover Story

INSTRUMENT –

12 Water Quality Parameters

The HI98494 Multiparameter Bluetooth Portable pH/EC/OPDO Meter is a product of Hanna Instruments’ philosophy to provide people with an easyto-use, common-sense approach to their testing needs – at an affordable price.

Designed to withstand harsh environmental conditions and ideal for field measurements, the HI98494 instrument is a waterproof combination of a portable, rugged meter and a digital probe.

MEASURED

1. pH The measure of how acidic/basic water is

2. ORP

Oxygen reduction potential 3. Conductivity The water’s capability to pass electrical flow 4. Dissolved oxygen The amount of oxygen in water 5. Temperature In °C

CALCULATED

6. pH-mV Probe measures a potential difference between the pH sample and a reference measured in units of millivolts

7. Absolute conductivity A conductivity measurement without temperature compensation

8. Resistivity The ability the water has to resist an electrical current, which is determined by the concentration of dissolved salts in the water

9. Total dissolved salts

Describes the inorganic salts and small amounts of organic matter present 10. Salinity The saltiness or amount of salt dissolved in a body of water 11. Seawater sigma The density at a given temperature 12. DO concentration The concentration of dissolved oxygen

TABLE 1 The HI98494 monitors 12 water quality parameters – of which five are measured and seven calculated. Each parameter is fully configurable The HI98494 allows for an easy one-point calibration of pH and EC sensors

Digital probe

The microprocessor-based intelligent probe (also called the HI7698494 sensor) comprises three sensors that are field replaceable, with auto-sensor direction and colour-coded caps: 1) Red – for pH and ORP measurements. 2) Blue – conductivity and all associated parameters. 3) Green – does DO measurements over long periods of time without the need for frequent calibration. The sensor also has a built-in temperature sensor and a removable protective shield. It is designed for a variety of water quality measurements both in situ and in active deployments in urban or natural waters. HI98494 has various probe cable lengths (4 m, 10 m, 20 m and 40 m) and the probe may be installed in a horizontal bank (fixed installation) or a vertical suspension (at a maximum depth of 20 m). Unlike probes that require a cable support for active deployments, the

The HI98494 has a multiparameter probe that is protected by a short, stainless steel, weighted protective shield. Its rugged design and weighted tip make it ideal for field use The Hanna LAB App can transform your iPhone, iPad and iPod Touch into a fully featured pH meter or a data management system when used in conjunction with a Hanna Instruments HALO pH probe and Bluetooth or HI98494 Multiparameter Bluetooth portable pH/EC/OPDO meter, respectively

probe can be manually lowered and raised by the cable due to its superior strength. The digital probe is suitable for confined locations (air vaults, river intakes, vertical wells) and tanks. It can be used in open moving water locations, such as rivers, streams, ditches (farmland drainage) and conveyance canals as well as lakes, ponds, wetland basins, infiltration basins and bays.

Data quality

In order to achieve accurate data, the location where the HI98494 is placed must be accessible for the duration of the measurement. It is important to consider seasonal flooding, freezing and other acts of nature. The data quality is also dependent upon the site location, service intervals, amount of coatings, sedimentation and vegetation, as well as the actual installation.

To protect the equipment, one must avoid exposure to wind, sun, foam, turbulence, air temperature gradients, extended periods of high flow, extended periods of high sediment, and floating debris. Dual charging battery system

Fitted with a rechargeable Li-ion battery and backup alkaline batteries to extend field use, the HI98494 has approximately 200 hours of use with the AA batteries (without Bluetooth or backlight) and 50 hours of use with the Li-ion battery (without Bluetooth or backlight).

Other features

The HI98494 meter has a good laboratory practice (GLP) feature whereby the last five calibrations are saved automatically. There is also a log-on-demand and an automatic logging feature that can log up to 45 000 samples for all parameters. A graphical display of the logged data can be viewed on the meter’s backlit LCD screen. The meter meets IP67 standards (30-minute immersion at a depth of 1 m) and the multisensor probe is totally sealed against water and dust, and meets the IP68 standard (continuous immersion in water).

Hanna LAB App

The HI98494 offers the ability to connect wirelessly to a smart device running the Hanna LAB

App. All logged data and files can be downloaded to the

Hanna LAB App on a smart device by using Bluetooth or a PC via a USB cable. The data logs can be retrieved through the app and sent via email or downloaded to a smart device for review.

The app is available via Google Play for Android devices or at the Apple Store for iPhones, iPads and Macs.

The app can also transform an iPhone, iPad and iPod Touch into a full featured

The microprocessor-based intelligent probe (also called the HI7698494 sensor) comprises three sensors that are field replaceable, with auto-sensor direction and colour-coded caps All logged data and files can be downloaded to the Hanna LAB App on a smart device by using Bluetooth or a PC via a USB cable

pH meter or a data management system when used in conjunction with a Hanna Instruments HALO® pH probe and Bluetooth or HI98494 Multiparameter Bluetooth portable pH/EC/OPDO meter, respectively.