Pool controller for pH, salinity and free chlorine levels
A complete solution for chlorine management, pH control, and chlorination disinfection of saltwater, equipped with measuring probes.
Hanna Instruments® BL135 models are controllers for saltwater pools with chlorine generation for pool disinfection. The controller allows continuous measurement and display of free chlorine, pH, and ORP (mV) values, as well as water and ambient temperatures and salt level.
BL135 saltwater pool controllers, together with the included BL130-7X0 salt chlorinator, are designed to automate and control free chlorine levels, pH, and disinfection in saltwater pools.
BL135 controllers automate chlorine generation and acid or base additions according to configured setpoints or periods.
How it works
The system uses electrolysis to convert dissolved salt (sodium chloride) in the water into hypochlorous acid (HOCl). HOCl is the most effective form of chlorine for eliminating pathogens, reaching its highest concentrations between pH 7.2 and 7.4, where it acts as both disinfectant and oxidant while providing residual protection.
Chlorine is generated by the BL130-7X0 chlorinator in a continuous flow system that requires the pool's recirculation pump to be active. In automatic mode, chlorine generation only starts once the pH reference value is reached. Acid or base additions are carried out via the integrated peristaltic pump with proportional control to prevent overdosing.
Measurement
The controller displays continuous readings of pH/ORP (redox), free chlorine, water and ambient temperature, and salt level as water circulates through the HI1038-2802 pH/ORP probe and the HI1040-1801 chlorine probe.
- HI1038-2802: combines pH, ORP, and temperature sensors plus reference and salinity electrodes in a single body. The ORP (redox) sensor is gold, the salinity pins are titanium, and the probe body is PVDF.
- HI1040-1801: contains a chlorine sensor for real-time monitoring of chlorine levels.
Monitoring and Controlling Hygiene
The BL135 system is based on a two-phase approach to automated chlorine management and water hygiene monitoring. The HI1040-1801 membrane-coated chlorine electrode measures the actual concentration of free chlorine (mg/L) in the pool water and is used for primary control. This probe contains a chlorine sensor for real-time monitoring of chlorine levels. The HI1038-2802 pH sensor is highly effective in measuring the alkalinity of the pool water, thus allowing real-time monitoring of disinfection effectiveness. This probe contains pH, ORP, and temperature sensors, as well as reference and salinity electrodes, in a single body.
The system uses the pH sensor to compensate for the signal, ensuring that even if the pH undergoes a slight variation, the chlorine reading remains accurate.
BL130-7X0 Chlorinator Control
The chlorinator control can automatically regulate chlorine production using set points and chlorine (Cl) measurements, as well as a fixed chlorine output.
It features a Fixed Mode, Pool Start Mode, "Boost" and "Programmed Boost" modes, and pool cover detection.
Depending on the size and needs of each pool, different versions are available based on the chlorinator capacity (g/h):
- BL135-20110 Pool controller for pH, salinity and free chlorine levels,
with salt chlorinator, capacity of 10 g/h - BL135-20120 Pool controller for pH, salinity and free chlorine levels,
with salt chlorinator, capacity of 20 g/h - BL135-20130 Pool controller for pH, salinity and free chlorine levels,
with salt chlorinator, capacity of 30 g/h
* Contact us for more details and prices.
| Specifications | Clorador BL130-710 | Clorador BL130-720 | Clorador BL130-730 |
|---|---|---|---|
| Pool dimensions | 30 m³ / 7,925 gal | 100 m³ / 26,417 gal | 150 m³ / 39,600 gal |
| Chlorine production | 10 g/hour | 20 g/hour | 30 g/hour |
| Power | 4 A | 5 A | 7 A |
| Bipolar cell design | 3 interlinked blades / 10 floating blades | 2 interlinked blades / 5 floating blades | 3 interlinked blades / 10 floating blades |
| Plate dimensions | 100 × 61 × 1 mm | 164 × 61 × 1 mm | 148 × 61 × 1 mm |
| Required flow rate | 150 to 450 L/min (40 to 119 GPM) | 150 to 450 L/min (40 to 119 GPM) | 150 to 450 L/min (40 to 119 GPM) |
| Recommended salinity | 4.0 to 6.0 g/L | 4.0 to 6.0 g/L | 4.0 to 6.0 g/L |
Main Features
- Integrated peristaltic pump with proportional control for pH regulation to prevent overdosing
- Chlorinator (salt electrolysis cell) to produce disinfectant chlorine from saltwater
- Available with a variety of cell sizes and production capacities to suit different pool sizes and needs
- Programmable modes for automatic control of the salt chlorinator via:
-
- Free chlorine sensor measurement
- Fixed mode and automatic mode
- Pool start-up mode
- Boost mode
- Pool cover mode
- Self-cleaning electrolysis cell reverses polarity to remove deposits caused by water hardness
- Dosing resumes on restart in case of power failure
- Manual control for pump priming
- Inlet level detection
- Ambient temperature sensor
- Activates the relay to activate the recirculation pump to prevent freezing Water in pipes
- Configurable recording interval
- Real-time graph display
- LED indicators for controller status, maintenance, and pump operation (dosing)
- Removing the magnetic front panel stops the internal movement of the pump
- Front connection panel for easy access
- USB port for recorded data and firmware updates
- BL135 model available with analog outputs (AO)
- Help section – overview of the instrument's main features and characteristics
How to order
Each BL135-20110 is supplied with:
BL130-710 salt chlorinator, BL130-415 flow cell panel, BL130-410 flow cell for the HI1040-1801 free chlorine probe (includes mounting brackets), Free chlorine probe HI1040-1801, HI1040A Replacement membrane cap for the HI1040-1801 free chlorine probe, HI7043S Gel electrolyte for the HI1040-1801 free chlorine probe 30 ml, HI1038-2802 Combined pH, ORP, salinity and temperature probe, HI7014 Checker® HC Pool Line, for free chlorine with initial reagent kit (6 tests) and sample cuvettes (2 units), BL130-900 Ambient temperature probe, pH probe holder for Ø 50 mm tube, Injector holder for Ø 50 mm tube, Injector, Valve for connection to the flow cell and accessories (2 units), Valve holder for Ø 50 mm tube (2 units), PVC tubing for aspiration and injection (5 m), Flow cell tubing (10 m), Tubing for peristaltic pump, Silicone oil (dropper bottle), Suction filter, Cable gland fittings (BL136 only), pH 4.01 and 7.01 standard solution (3 sachets each), 470 mV ORP test solution (3 sachets), 5.00 ppt salinity calibration standard (3 sachets), Power cord, Quality certificates (instrument, probes, chlorinator, accessories), Quick reference guide with QR code to download the instruction manual.
General Specifications
| Parameter | Range | Resolution | Accuracy | Calibration | Temperature Compensation |
|---|---|---|---|---|---|
| pH | 0.00 to 14.00 pH* | 0.01 pH | ±0.05 pH (at 25 °C / 77 °F) | Standard pH: automatic buffer recognition, two points (4.01 pH, 7.01 pH, 10.01 pH). Process pH: adjustable, single point | Automatic temperature compensation for pH (range: –5.0 to 105.0 °C / 23.0 to 221.0 °F) |
| ORP (mV) | ±2000 mV | 1 mV | ±5 mV (at 25 °C / 77 °F – ORP standard) | Adjustable, single point | — |
| Free Chlorine | 0.00 to 10.00 mg/L | 0.01 mg/L | ±0.1 ppm ±5% of reading** | User single-point calibration, custom point | Automatic temperature compensation for chlorine (range: 15 to 40 °C / 59 to 104 °F) |
| Salinity | –5.0 to 105.0 °C (23.0 to 221.0 °F)* | 0.1 g/L | ±0.2 g/L NaCl or ±2% of reading, whichever is greater | Automatic; single-point calibration at 5.00 g/L or 35.00 g/L | Automatic temperature compensation for salinity |
| Temperature | –5.0 to 105.0 °C (23.0 to 221.0 °F)* | 0.1 °C / 0.1 °F | ±1.0 °C / ±1.8 °F (at 25 °C / 77 °F) | — | — |
| Air Temperature | –30.0 to 80.0 °C (–22.0 to 176.0 °F)* | 0.1 °C / 0.1 °F | 0.5 °C | — | — |
pH Compensation: Automatic pH compensation for chlorine, range 6.0 to 8.0 pH*
Data Logging Memory
- Automatic logging of pH, ORP, salinity, chlorine, air and water temperature measurements
- 300 days of logging, depending on the selected logging interval
- 100 batches (when memory is full, new entries overwrite the oldest data)
Data Log Type
Event type: configuration, alarms, errors, warnings, calibration, power failure
Data Log Interval
Configurable logging interval: 30 seconds; 1; 5; 15; 30; 60 minutes
Data Log Export Options
Export to USB drive (USB-C port) in .CSV format
USB-C
Data export and software update
Notes: * The pH and temperature range may be limited by probe limits. ** When taking measurements within ± 0.5 pH, ± 2 °C and ± 25% of the free chlorine calibration value.
Additional Specifications
| Feature | Description |
|---|---|
| pH Control | Uses pH measurement. Start-up delay when powering on the unit. Proportional power supply using an adjustable set point and adjustable proportional band. Adjustable dead band between 0.01 and 0.20 pH (Technician Mode only). Overdosing protection via overfeed timer |
| Chlorinator Control | Uses chlorine measurement. Programmable modes: Chlorine boost, Scheduled boost, Pool start-up, Pool cover detection. Chlorine control: AUTO, FIXED, Manual (On/Off) |
| Internal Pump Control | Pump flow control from 0.5 to 3.5 L/h (0.13 to 0.92 gal/h). Maximum outlet pressure of 1 atm (14 psi) |
| Manual Pump Control | The magnetic front plate (covering the pump's internal moving part) activates "Hold" status when removed, stopping the pump |
| Pool Start-up Mode | Simplified pool start-up procedure. Manually enabled or disabled from the controller menu. Ensures a 12-hour dosing cycle to reach the intended set point. Automatically disabled when the target value is reached or the 12-hour timeout expires |
| Pool Cover Detection | Reduces chlorine production when pool cover is detected |
| Freeze Protection Mode | Ambient temperature measurement triggers the relay to activate the recirculation pump, preventing water from freezing in the pipework |
| Chlorine Boost | Ensures high chlorine levels are reached in a short time |
| Cold Water Protection | Reduces chlorine production when pool water is below 15 °C (59 °F) |
| GLP (Good Laboratory Practice) | Chlorine, pH, ORP, salinity |
| Meter Password Protection | Configuration, calibration and log retrieval protected by password |
| Relays | Alarm relay (SPDT): triggered by selectable alarm conditions for chlorine, pH, ORP, salinity and temperature. Acid/base auxiliary pump relay (SPST). Recirculation pump relay (SPDT). All relays are protected by 2 A time-delay cartridge fuses, 5 × 20 mm. Replace only with glass/ceramic time-delay cartridge fuses, 5 × 20 mm, of the same rating. All relays are rated for 250 VAC / 30 VDC and 2 A resistive load. Note: for inductive loads, a suitable external snubber circuit must be connected to prevent damage to the relay contacts |
| Analog Outputs | 3 × 4–20 mA outputs with galvanic isolation, user-configurable. Current sensing resistance ≤ 500 Ω. Accuracy < 0.5% FS |
| Digital Inputs | 5 × digital inputs with powered contact and galvanic isolation: Acid/base tank low level, Hold mode, Pool cover sensor, Probe flow |
| Probe Inputs | HI1038-2802 digital pH probe: pH, ORP, salinity and temperature sensors with matching connector, IP65 connector, galvanic isolation, RS485 interface. HI1040-1801 digital chlorine probe: galvanic isolation, RS485 interface, IP65 connector. Ambient temperature sensor |
| Power Supply | Input: 100–240 VAC; 50/60 Hz; 3 A. Output: 24 VDC; 7 A |
| Housing | Wall-mounted, IP65 rated, shockproof |
| Environment | 0 to 40 °C (32 to 104 °F), maximum relative humidity 95%, non-condensing |
| Dimensions | 300 × 205 × 95 mm (11.8 × 8.07 × 3.7") |
| Weight | 4100 g (144.6 oz.) |
HI1038-2802 Specifications: pH/ORP/Salinity/Temperature Probe
| Parameter | Value |
|---|---|
| pH Range | 0.00 to 12.00 pH |
| ORP Range | ±2000 mV |
| Salinity Range | 0.0 to 40.0 g/L |
| Temperature Range | 0.0 to 70.0 °C (32.0 to 158.0 °F) |
| Reference | Ag/AgCl reference electrode (3.5 M KCl) |
| ORP Sensor | Gold |
| Junction | Cloth |
| Match Pin | Titanium |
| Body | PVDF |
| Top Thread | 3/4" NPT |
| Connector | DIN connector |
| Max. Pressure at 25 °C | 3 bar (43.5 psi) |
Probe Ordering Codes
| Code | Cable Length |
|---|---|
| HI1038-2802 | 2 m (6'7") |
| HI1038-2805 | 5 m (16'5") |
| HI1038-2810 | 10 m (32'9") |
| HI1038-2815 | 15 m (49'3") |
| HI1038-2820 | 20 m (65'7") |
| Parameter | Value |
|---|---|
| Free Chlorine Range | 0.00 to 10.00 ppm |
| Temperature Range | 0.0 to 40.0 °C (32.0 to 104.0 °F) |
| Calibration | Single-point process calibration |
| Body | PVDF |
| Top Thread | 3/4" NPT |
| Connector | DIN connector |
| Max. Pressure at 25 °C | 3 bar (43.5 psi) |
| Probe Ordering Code | HI1040-1801 |
BL130-900 Specifications: Ambient Temperature Probe
| Parameter | Value |
|---|---|
| Range | –30.0 to 80.0 °C (–22.0 to 176.0 °F) |
| Resolution | 0.1 °C / 0.1 °F |
| Accuracy | ±0.5 °C |
| Cable Length | 3 m |
| Fast Shipping | No |
|---|