BL-121 Pool and Spa Controller

The BL-121 Swimming Pool Controller is a complete system designed for maintaining swimming pool, hot tub, and spa disinfection water quality.

The controller is available in two versions:

• Optional bypass flow cell included (BL-121-20) - ease of maintenance enhanced by allowing calibration and maintenance of the probe without the need to shut down the recirculation pump
• Inline system (BL-121-10) allows for direct installation of probe and chemical injection fitting into existing piping.

Key features:

• Multi-coloured LED indicators for dosing
• Meter status and service
• USB Connectivity
• Real-time graph display
• Automatic logging
• Programmable alarms
• Password protection

More information:

BL-121 uses a multiparameter digital HI-1036-1802 probe that incorporates pH, ORP and temperature sensors along with a matching pin. All readings are measured within the probe and the data transferred to the controller by a digital connection.

A digital connection and matching pin provide for stable, reliable measurement. Without these two components, electrical noise from recirculation pumps and ground loops can interfere, causing erratic readings and premature probe failure.

BL-121 has two built-in peristaltic chemical feed pumps that are proportionally controlled with adjustable flow rates. One of the pumps is used to dose acid while the other is used to dose chlorine. The effectiveness of the available Chlorine, as determined by ORP, is inversely related to the pH value of the water. A pool with a fixed concentration of chlorine will show a decrease in ORP as the pH of the water increases.

BL-121 also features a dosing consent feature that will not dose chlorine until the pH value is first corrected. It is possible to have a low ORP value even though there is sufficient chlorine. The dosing feature avoids this situation as well as preventing chemical wastage and having a higher chlorine concentration level than desired.

HI-1036-1802 Multiparameter Digital pH, ORP, Temperature Probe

HI-1036-1802 is a digital probe that measures pH, ORP, and temperature. This probe also incorporates a potential matching pin. The matching pin is considered the ‘earth ground’ connection and is used to prevent ground loop effects from causing erratic readings and damage to the system.

pH glass has been chosen to produce stable quick equilibration even in low conductivity waters. Additionally, the pH sensor is designed to produce a mV value near pH 4 (not pH 7 like typical sensors) should it stop working. A broken pH electrode that produces mV value near pH 7 would produce an alarm state and disable any pump activated.

The ORP sensing surface is a large smooth surfaced platinum band that encircles the circumference of the temperature probe. It is referenced to Ag/AgCl reference electrode (3.5M KCI).

The ORP and pH sensors and reference electrode all use a differential measurement technique designed to deliver accurate results under adverse conditions that may cause conventional pH probes to produce erroneous measurements.

The HI-1036-1802 probe with its differential amplifiers greatly reduces inaccuracies caused by ground loops which may exist between process and instrument grounds. With the differential technique, a ground loop current flows through the low impedance path of the matching pin and provides immunity to the measurement signals. In addition, the probe converts these measurements to a digital signal to eliminate noise and static due to high impedance signals carried by cable.

Both the HI-1036-1802 and the BL-121 Pool controller promote the health and safety of pool and spa water.

Liquid Crystal Display

A versatile display allows three display modes. The LCD can display all three parameters at once, a 3-second cycle of single parameters, or a real-time plot screen with options for parameter selection, zooming, and log recall.

Datalogger

For compliance monitoring, the BL-121 has a built-in datalogger. Measurement readings are logged every 10 seconds with a new log starting each new day or when the instrument is calibrated. Logged data include pH, ORP, and temperature values, last calibrated data, setup configuration, and any event data.

Analogue outputs

Three 4-20 mA analogue outputs are available for users that wish to connect to an external chart recorder or datalogger to monitor any of the three measured parameters. The outputs are scalable, offering increased flexibility and better resolution as needed.

Additional features

Additional features of the BL-121 include LED indicators for dosing, meter status and service, real-time graph display, programmable alarms, and password protection.

Liquid Crystal Display - A versatile display allows three display modes

The digital probe measures pH, ORP, and temperature. This probe also incorporates a potential matching pin.

HSG282 compliance handled for you

Do you need to comply with HSG282 guidelines? This 2017 HSE legislation helps protect your business and your customers from risk caused by dangerous pathogens. Any heated, agitated water, such as hot tubs and spa pools used for commercial purposes, can be a breeding ground for legionella, e-coli and more.

The BL-121-20 automates HSG282 pH compliance, collecting consistent readings for your records and dosing the water for pH and chlorine balance to ensure optimal sanitation. Automatic logging helps you keep your records in perfect condition over five years without manually taking readings yourself twice daily in line with HSG282 hot tub regulations.

As with all Hanna Pool Line products, the BL-121-20 is designed for accuracy and ease of use when measuring the pH in hot tubs and spa pools. We make compliance with HSG282 effortless, helping you to keep yourself safe from negative press, legal costs and potential loss of business.

Learn all about HSG282 compliance, what it means for your business and why you might want to follow this legislation in our complete guide here.