If you intend to be the future owner of a swimming pool or if you are already a well-established company that builds swimming pools, you should know that it is necessary to maintain cleanliness and sanitation of water.
The chemical reaction that is essential for water sanitation is oxidation. During the oxidation process in pool water, an electron exchange occurs between chlorine (or some other oxidant) and a contaminant in the water. In this way the contaminant is inactivated and chemically inert.
The most commonly used means for sanitation and treatment of pool water is chlorine because it kills bacteria, viruses, other microorganisms, as well as other contaminants very successfully. Besides chlorine, some other oxidation methods of pool sanitation include the use of bromine, iodine, ozone …
If we talk about oxidation in pool water, important parameter is ORP.
ORP or oxidation-reduction potential is a water quality parameter that measure oxidizing capacity in water. Or to put it another way, ORP is the cleanliness of the water and its ability to break down contaminants. ORP as parameter is measured in swimming pool water and drinking water (chlorine is used to sanitize drinking water) and it tells us how effective chlorine or some other oxidizers are in the water.
For measuring ORP we use ORP probes that detects voltage between electrodes and gives us a value whose unit of measurement is milivolts (mV). Oxidizers will show positive mV charge, while contaminants will show negative mV charge. Various ORP controllers or testers can help us in determining the quantity of an oxidizer that is beeing used for sanitation of water. Although optimal concentration levels vary depending on the type of cleaning agent, the ORP level should be maintained above 650 mV for pools and spas treated with chlorine, bromine or iodine.
To measure ORP value, Hanna Instruments have various devices that can help you in sanitation of pool water. From automated process controllers, to simple hand testers, ensure carefree swimming and pool fun with Hanna Instruments.
Chlorine, pH, ORP, and Temperature Analyzers - PCA300 Series
The Hanna Instruments PCA310, PCA320, PCA330 and PCA340 series of chlorine, pH, ORP and temperature analyzers are microprocessor controlled, process analyzers which continuously monitor a sample stream for chlorine content, pH, ORP and temperature values. The PCA Analysers uses DPD Colorimetric method for determining chlorine.
- 4 models available for monitoring chlorine, pH, and ORP levels
- Two separate selectable 0-20 or 4-20 mA signal output (PCA340 only)
- User-friendly interface simplifies setup and maintenance
pH/ORP Controllers - BL122 • BL123
with Cloud Connectivity
BL122 and BL123 are designed to maintain constant pH and disinfectant levels in swimming pools, hot tubs, and spas and offer the added benefi t of allowing remote
connection and access to devices via the Hanna Cloud web app. These controllers are available in two configurations. The basic version is the inline model which allows for direct installation of probe and chemical injection fittings into existing piping. A panel mounted version with a bypass fl ow cell is also available. The bypass flow cell allows for calibration and maintenance of the probe without having to shut down the recirculation pump.
Hanna Cloud:
Hanna Cloud is a web-based application that connects you to measurement devices such as the BL122 and BL123. Measurements and data storage are accessible from your PC, tablet or phone. Measurements, trends, history, device settings, alarms, and messages are transmitted to your “Dashboard” as your instrument measures and controls your process.

pH/ORP Controllers - BL120 and BL121
with Built-In Chemical Feed Pumps
These Swimming Pool Controllers are a complete system designed for maintaining
swimming pool, hot tub, and spa disinfection water quality. These controllers are available in two configurations. The basic version is the in-line model which allows for direct installation of probe and chemical injection fittings into existing piping. A panel mounted version with a bypass flow cell is also available. The bypass flow cell allows for calibration and maintenance of the probe without having to shut down the recirculation pump.
Pool Line ORP Controller and Dosing Pump - BL101
Engineered to be an inexpensive solution for homeowner and maintenance companies to maintain the ideal ORP at all times of a swimming pool or hot tub. The BL101 Pool Line ORP Controller and Dosing Pump is a complete solution with both a process controller and a chemical dosing pump. Simply insert the probe and injection valve in-line with the re-circulation pump and supply the oxidizer (i.e. chlorine) to be dosed.
- All in one solution for maintaining the proper ORP value
- Industrial process probe with 1/2″ NPT threads for insertion into re-circulation line
- Input for level controller or flow switch
For measuring on the spot we can recommend a wide range of portable meters.
Multiparameter Waterproof Meter – HI981954
HI981954 Pool Line
Multiparameter Waterproof Portable
pH/ORP/EC/Temperature meter is made for measuring key water quality parameters in swimming pool, hot tub, or spa water. This is an advanced meter uses a single weighted probe with multiple sensors to measure multiple parameters simultaneously and display results as pH, pH in mV, ORP, conductivity (EC), total dissolved solids (TDS), salinity, and temperature.
The meter has a built-in pressure transducer for barometric pressure readings.
- One probe with field replaceable pH/ORP, EC
and temperature sensors
- Auto-ranging for EC and TDS readings
- Display up to 11 measurements simultaneously
Professional Waterproof Portable pH/ORP/ISE Meter – HI981914
HI981914 Pool Line
Professional Waterproof Portable pH/ORP meter is
made for measuring pH and ORP of a swimming pool, hot tub, or spa water. This is an advanced meter with many features including Hanna’s exclusive CAL Check pH electrode diagnostics that is used to identify potential problems including when to clean the electrode, check a buffer for contamination and the overall health of a pH electrode. This function can be used to identify issues with process probes that have a BNC connector.
- Laboratory grade measurements in a portable
- CAL Check advanced probe diagnostics
• Troubleshooting tool for the maintenance of process probes
Waterproof Portable pH/pH-mV/ORP/Temperature Meter with Sensor Check™ – HI991003
The HI991003 is a compact, waterproof, portable pH/pH-mV/ORP/temperature meter that is supplied complete including a rugged carrying case and a unique titanium body pH/ORP electrode that has a built-in temperature sensor. This meter comes with our unique Sensor Check™ feature that allows the user to determine the electrode status at any time. The meter features a large, dual level LCD display for easy viewing of the pH, pH-mV, ORP, temperature, and status indicators. The operation of the meter is simplified to two buttons. The HI991003 has an exceptional long battery life of 1400 hours of continuous use.
- Automatic Temperature Compensation
- Automatic Two-Point Calibration
- Waterproof
For Family pools and various smaller pools you can use Hanna Instruments testers.
ORP/Temperature Pool Line Tester – HI981204,
HI981204 Pool Line ORP and temperature meter is made for measuring the oxidation (chlorine) level of swimming pool, hot tub, or spa water. This lightweight, waterproof tester offers high accuracy ORP, and temperature measurements in a single handheld unit.
- Waterproof
- Replaceable ORP electrode
- Simultaneous display of ORP & temperature
pH/ORP/Temperature Pool Line Combo Tester – HI981214
pH/ORP meter is made for measuring pH and ORP of a
swimming pool, hot tub, or spa water. This
lightweight, waterproof tester offers high accuracy
pH, ORP, and temperature measurements in a single
handheld unit. No more switching between meters for
your routine measurements.
- Waterproof
- Replaceable pH electrode
- Automatic calibration