8. CHEMICAL DOSING UNIT USERS MANUAL
General Safety Guidelines
- In emergencies the instrument should be switched off immediately. Disconnect the power cable from the power supply.
- When installing always observe local regulations.
- Manufacturer is not liable for any unauthorized use or misuse of this product that may cause injury, damage to persons and / or materials.
- The controller should be interlocked with a no-flow protection device to automatically shut-off the peristaltic pumps when there is no flow.
- Peristaltic pumps and accessories must be serviced and repaired by qualified and authorized personnel only.
Instrument must be accessible at all times for both operating and servicing.
- Access must not be obstructed in any way
- Always discharge the liquid end before servicing the instrument. Empty and rinse the liquid end before working on a peristaltic pump which has been used with hazardous or unknown chemicals.
- Always read the material safety data sheets for all chemicals used.
- Always wear protective clothing when handling hazardous or unknown chemicals.This instrument must be operated / serviced by trained technicians only.
- All connection operations must be performed while the instrument is not connected to main power supply.
- Adequate measures should be taken to prevent cross connection of chemicals.
- Chemical feeding should be stopped during backwash cycles and periods of no flow as these conditions may introduce the potential for chemical overdosing.
- Not doing so may result in elevated chemical concentrations into the pool or spa.
- If the supply cord is damaged it must be replaced by either the manufacturer, it’s nominated service agent or similarly qualified person in order to avoid a hazard.
The chemical control unit ensures that the correct residual level of Perox is maintained within the swimming pool while also correcting pH as required. Perox residual is maintained by the relationship to ORP as set out in the operating instructions.
8.1 Introduction
The Hydroxypure Chemical Dosing unit is a fully integrated controller ideal for a broad range of swimming pool designs.
The chemical dosing is performed with high-quality integrated peristaltic pumps, which feature low maintenance tubing sets and roller assemblies.
The Hydroxypure Chemical Dosing unit ensures that the correct residual level of Perox is maintained within the swimming pool while also correcting pH as required. Perox residual is maintained by the relationship to ORP as set out in the operating instructions.
Working ranges are:
pH : from 0 to 14 pH
ORP: from 0 to 999 mV
All information is provided through a large LCD display screen. The controller can be easily programmed using the revolutionary wheel control system. The Hydroxypure Chemical Dosing unit is housed in an IP65 plastic box.
8.2 The Wheel
Located in the upper right side of the Hydroxypure Chemical Dosing unit there is a wheel that is used to control the instrument. The wheel can be rotated in both directions to scroll over the menus and/or pressed to confirm a highlighted selection/value.

![]() Figure 8-1 SCROLL |
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![]() Rotate wheel to scroll through menus or options |
Figure 8-2 SELECT |
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Press wheel to select highlighted option |
8.3 Flow Switch (Installations Outside AUS/NZ)
The controller should be interlocked with a flow switch to automatically shut-off the peristaltic pumps when there is no water flow.
The flow switch should be connected to the ‘B’ connector on the Hydroxypure Chemical Dosing unit.
8.4 Main Screen
When in the normal operating mode the Hydroxypure Chemical Dosing unit shows the following main screen:
The Main Screen is divided into 3 zones:
(1) UNITS: “pH†is the measuring unit for pH probe; “mV†is the measuring unit for ORP probe.
(2) VALUES: These numbers are the measured values read by the probes.
(3) Peristaltic pumps STATUS: These fields are related to the current peristaltic pumps status and instrument activity.
Figure 8-3 Main Screen
Display | Explanation | What to do if occurs |
FEED ON | Peristaltic pump is dosing chemical product into ON/OFF mode. | No action required. |
FEED XX% | Peristaltic pump is dosing chemical product into PROPORTIONAL mode. | No action required. |
FEED OFF | Peristaltic pump is OFF. | No action required. |
LOW TANK | Chemical product tank is almost empty. | Check chemical tank. Restore correct level. Note that no chemical will be dosed when this alarm shows. |
NO FLOW | External flow contract stops both the pumps. | Check flow. |
OK | Set point reached. | No action required. |
FEED LIMIT | Time for dosing exceeded. Dosing alarm. | Increase feeding delay time from PARAMETERS options. |
PROBE FAIL | Stuck while reading values. | Check probe for proper functioning. Note: does not necessarily mean the probe has failed. |
DELAY | Peristaltic pump activity delayed. Countdown in progress. | If not requested check PARAMETERS options. |
WAIT PH | pH priority dosage over ORP dosage. | If not requested check PRIORITY options. |
Table 8-1 Main Screen Key
8.5 Passcode
To grant access into the “Main Menu” press the wheel from main screen and enter the passcode. If this is the first time the unit has been turned on then the passcode is 0000 (factory pre-set). Press wheel 5 times to enter into the “Main Menu”. Otherwise press the wheel 1 time and enter the passcode. Numbers can be selected rotating the wheel
Figure 8-4 Passcode input
To set a new passcode choose “ADVANCE SETTINGS” from “SETTINGS & CALIBRATION MENU” , move on to “New Pcode”, click on the wheel and then enter a new four number code. Click on “EXIT” and choose “YES” to save request. The new passcode is now ready.
Figure 8-5 Changing Passcode
Lost passcode:
Please note down your passcode (if changed). In the unfortunate event that you forget or misplace the code, please call your local distributor for the unlocking procedure.
8.6 Quick Status Check
From the Main Screen rotate the wheel to review the primary instrument parameters and current status conditions. This mode will allow readings to be observed about the current status of the Hydroxypure Chemical Dosing unit.
Figure 8-6 Quick Status Screen
8.7 Main Menu
To gain access into the ‘Main Menu’ enter the passcode. Rotate the wheel to scroll through all the options available.
Figure 8-7 Main Menu Structure
8.8 Set Points Menu
The Set Points menu is used to define the corresponding set point value for ORP and pH controller operation.
The operation of the controller is based on the following principles:
I. Values can be set to operate the peristaltic pump using 2 set-points and proportion (%).
II. It is recommended to always use Proportional (%) mode with the Hydroxypure system.
III. Desired set point: The desired set point is the lower of the two (2) range set points for both pH and Perox.
IV. Range (response rate): The distance between the lower and upper set points is the range. The larger the range, the slower the response of the unit. The smaller the range the faster the response of the unit.
V. When adjusting the lower set point, always ensure that the upper set point is also adjusted to maintain the desired range.
VI. Proportion (dose rate): The proportion or %, is the rate at which the unit will dose when required measure in seconds per 100 seconds.
The proportion is always set at ‘00%’ for the lower of the set points. Adjust proportion at the upper set point.
Set Points Menu Structure
Figure 8-8 Set Points Menu Structure
8.8.1 Settings
The Hydroxypure Chemical Dosing unit comes pre-set with parameters for pool. In most cases, no adjustment will be required to the pre-set parameters. However no 2 pools are the same and some adjustment may be required.
Range (200) | Mode: Proportional | |
mV upper | 480 | 50% |
mV lower | 280 | 00% |
Table 8-2 Preset ORP Values for a 40-60kL Pool
Range (0.6) | Mode: Proportional | |
pH upper | 8.4 | 50% |
pH lower | 7.4 | 00% |
Table 8-3 Preset pH Values for a 40-60kL Pool
8.8.2 Set pH
Figure 8-9 pH Setup
Figure 8-10 Setting Operating Values for pH
Example: Proportional mode with a range of 7.00pH (0%) and 8.00pH (100%). In this mode the pH peristaltic pump will be ‘ON’ for values greater than 7pH and it’ll be ‘OFF’ for values lower than 7pH. For values of 7.5pH peristaltic pump will be ‘ON’ for 50 seconds out of every 100 seconds
Figure 8-11 Saving pH Setup
Pool Size | Range | Proportion (%) | Response rate |
---|---|---|---|
< 20kL (5,300 US gal) | 7.2-8.4 | 30% | Slow |
40-60kL (10,600 -15,900 US gal) | 7.4-8.4 | >50% | Average |
> 80kL (21,100 US gal) | 7.4-8.4 | 100% | Fast |
Table 8-4 pH Settings for Different Pool Sizes
Should any adjustment be required, adjust the desired set point in increments of 0.1. The proportion (%) can be adjusted as desired. Allow the pool to circulate for 48 hours before testing and adjusting again.
To end the procedure, move the cursor on ‘OK’ and press the wheel to proceed to ‘Save’ request screen. Move wheel on ‘YES’ to save or ‘NO’ to discard changes.00%
8.8.3 Set mV
Figure 8-12 Accessing ORP Set Up Menu
Figure 8-13 Setting Operating Values for ORP (mV)
Example: Proportional mode with a range of 100 between 600mV (100%) and 500mV (0%). In this mode the Perox peristaltic pump will be ‘ON’ for values higher than 500mV and it will be ‘OFF’ for values lower than 500 mV. For values of 550mV peristaltic pump will be ‘ON’ for 50 seconds out of every 100 seconds.
mV set point comes preset to 280mV, set point adjustments may be required to reach 100ppm of Perox (hydrogen peroxide). Readings will vary from region to region depending on conditions. Some adjustment may be required.
Figure 8-14 Saving mV (ORP) Setup
Should any adjustment be required, only adjust the mV settings by no more than 5mV at once. Allow the pool to circulate for 48 hours before checking and adjusting the system again.
Important: The lower the mV settings, the higher the residual hydrogen peroxide level will be. Reduce the mV to increase residual hydrogen peroxide levels.
Pool Size | Range | Proportion (%) | Response rate |
---|---|---|---|
< 20kL (5,300 US gal) | 200 | 30% | Slow |
40-60kL (10,600 -15,900 US gal) | 200 | >50% | Average |
> 80kL (21,100 US gal) | 100 | 100% | Fast |
Table 8-5 mV (ORP) Settings for Different Pool Sizes
To end procedure move cursor on ‘OK’ and press wheel to proceed to ‘Save’ request screen. Move wheel on ‘YES’ to save or ‘NO’ to discard changes.
8.9 Dosing Mode Menu
‘Dosing Mode Menu’ menu allows manual operation of one or both of the peristaltic pumps for a programmable time.
8.9.1 Automatic Dosing
Move on ‘Mode’ then press wheel. Select ‘Auto’ mode to run the peristaltic pumps according to the set points and chemical demand. Move on ‘EXIT’ then press wheel.
Figure 8-15 Setting Dosing Mode
8.9.2 Manual Dosing
I. Move on ‘Mode’ then press wheel. Rotate the wheel to select ‘MAN PUMP pH’ to manually operate pH peristaltic pump or ‘MAN PUMP ORP’ for the Perox peristaltic pump. Press the wheel over the selected pump. The time setting will then appear.
II. Press wheel to move cursor to ‘TIME’. Choose a working time between 0 (disabled) or 99 minutes.
III. Move to ‘EXIT’ then press wheel. Choose ‘YES’ to save changes.
IV. Main display will show a countdown including the selected peristaltic pump (left for pH peristaltic pump, right for Perox peristaltic pump).
V. The default setting for the operating mode is ‘AUTO’.
VI. Following any period of ‘MAN PUMP’ activities, the unit will revert to ‘AUTO’ mode.
8.9.3 Manual Dosing -Pumps Functionality.
- Only two conditions can be stored in the Dosing Mode, either “OFF” or “AUTO”
- The controller should NEVER be allowed to stay in a Manual Dose state
- If Dosing Mode is set to “OFF”, it’ll stay on “OFF” until it is changed. Even if the unit is powered down
- During or after manual dose is set, if user returns to the menu, manual dose is cancelled and Dosing Mode will return to “AUTO”, unless it was “OFF” first.
8.10 Settings & Calibration Menu
Setting and calibration menu allows the user the access to calibrate the sensor and to advanced settings of the controller amongst others. The structure of the advance settings menu is the following:
Figure 8-16 Settings & Calibration Menu Structure
8.10.1 Sensor Calibration

8.10.1 pH Probe
pH calibration procedure should be performed annually. There are two modes of calibration for the pH probe
Figure 8-17 Accessing Probe’s pH Calibration Menu
Figure 8-18 Calibration Menu
A. Fast Calibration:
This option allows the user to calibrate the sensor without the need to remove it from the line or using buffer solutions. This is a one point calibration.
User will require a reference value for the value for the set point to be defined.
Select P with the Wheel and press. Rotate the wheel to the desired pH value ‘Cal. at’ and then press to confirm.
To end procedure move cursor on ‘OK’ and press wheel to proceed to ‘Save’ request screen. Move wheel on ‘YES’ to save or ‘NO’ to discard changes.
Figure 8-19 pH Fast Calibration
B. Full Calibration
This involves two calibration point and requires two buffer solutions. Default pH buffer solutions are pH 4.00 and pH 7.00. These are available from your nearest Waterco branch.
From ‘Menu Calibration’ choose ‘pH probe’
In the following example, the instrument will calibrate pH using default buffer solutions values.
Calibration: 1st Point
In ‘pH Calibration’ menu, move wheel on ‘P1’ then press to enter into first point calibration submenu.
Prepare 7.00pH buffer solution and dip probe’s sensor tip into it. Wait until the reading value is stable according to the buffer solution value and then rotate the wheel until it is the same on the display (‘Cal. at’). Default value is 7.00pH.
Move cursor on ‘OK’ and press wheel to proceed to next step.

Figure 8-20 First pH Calibration Point
Calibration: 2nd Point
In ‘pH Calibration’ menu move the wheel on ‘P2’ then press to enter into second point calibration submenu. Prepare 4.00pH buffer solution and dip probe’s sensor tip into it. Wait until the reading value is stable according to the buffer solution value and then rotate the wheel until it is the same on the display (‘Cal. at’). Default value is 4.00pH.
Figure 8-21 Second pH Calibration Point
Move cursor on ‘OK’ and press wheel to proceed to next step.

To end procedure move cursor on ‘OK’ and press wheel to proceed to ‘Save’ request screen. Move wheel on ‘YES’ to save or ‘NO’ to discard changes.
C. ORP (mV) Calibration
mV calibration should be performed annually. This procedure involves one point (P1) calibration. From ‘Menu Calibration’ choose ‘mV probe’.
Figure 8-22 Calibrating ORP (mV)
I. Measure buffer solution temperature and verify that it is the same as printed on solution’s label.
II. Remove protective cap from probe and wash probe’s tip in water. Then dry it by shaking the probe in air.
III. Set ‘mV Def’ value to match buffer solution value then put probe’s tip into buffer solution and wait until the display shows a stable reading in the ‘Reading’ field.
IV. To end procedure move cursor on ‘OK’ and press wheel to proceed to ‘Save’ request screen. Move wheel on ‘YES’ to save or ‘NO’ to discard changes. If an error occurred during calibration procedure then the instrument will show an error message and will ask to proceed to a new calibration, cancel current operation or restore default settings.
8.10.2 Flow Switch
Flow contact input can be enabled to stop all dosing activities using a DIRECT contact (N.O. normally opened contact) or REVERSE contact (N.C. normally closed contact) flow switch or disabled. The controller is supplied with an appropriate cable for this connection (International units). Move wheel for enabling and changing contact logic (DIRECT or REVERSE).
Factory pre-set for international units is ‘REVERSE’
Figure 8-23 Flow Detection Menu
To end procedure move cursor on ‘OK’ and press the wheel to proceed to ‘Save’ request screen. Move wheel onto ‘YES’ to save or ‘NO’ to discard changes.
8.10.3 Data Logging
This function records instrument activity (date, hour, temperature, alarms, outputs, etc). It starts for a selected frequency period (every) at requested time (time).
Figure 8-24 Data Logging Options
Set ACTIVE to “enabled” to activate log recording.
Set recording start time in “TIME” (time format 23h: 59min)
Set recording frequency in “EVERY” (time format 23h: 59 min)

8.10.4 Advance Settings
Define advance setting of the controller such feeding delay, passcode and operation mode. In SETTING & CALIBRATION MENU select ‘ADVANCE SETTINGS’
Figure 8-25 Advance setting options
- Feeding Delay
- Mode

- New passcode (Pcode)

Warning: If changing the passcode from ‘0000’, note the new passcode in a secure location.
- TAU: represents the averaging factor of the pH and ORP reading. The higher the value the higher the number of values that are used in the calculation of the average reading before it is displayed on screen. Factory Default value is 5.
- To end the procedure move cursor to ‘OK’ and press wheel to proceed to ‘Save’ request screen. Move wheel to ‘YES’ to save or ‘NO’ to discard changes.
8.10.5 Digital Inputs
This function sets contact type for each digital input. Contact type can be set as N.O. (normally open contact) or N.C. (normally closed contact). Using the wheel move on required input, press wheel then rotate the wheel to choose between N.O. or N.C.
Figure 8-26 Digital Inputs Menu
To end procedure move cursor on ‘OK’ and press the wheel to proceed to ‘Save’ request screen. Move wheel onto ‘YES’ to save or ‘NO’ to discard changes.
8.10.6 System Reset
To restore the unit to default values (including password) once in the ‘System Reset’ menu, press wheel then change value to ‘ON’. Press wheel, move on ‘OK’ then press wheel.
The instrument display will show ‘CHECKSUM ERROR’. Press wheel to return into ‘Main Menu’. Move to ‘EXIT’, then press wheel. The instrument is now restored to factory default.
Repeat all calibration procedures and programming parameters.
Figure 8-27 Reset Function
8.11 Alarms Menu
Use this menu to define the alarm of the instrument.

8.11.1 Dosing Alarm
Use this menu to assign a maximum time to the peristaltic pumps for reaching the set point. If set time ends and the peristaltic pumps are still dosing, within this menu is possible to STOP them or just to show an alarm message (continue to DOSE). Function can be disabled selecting ‘OFF’ instead of a number minutes.
The dosing alarm can be set for both or just one peristaltic pump. This feature is used to help prevent overdosing of chemical in cases of probe failure or incorrect readings etc.
Parameter | Time | Action after Activating Alarm |
mV | 470min | DOSE |
pH | 480min | DOSE |
Table 8-6 Dosing Alarms Default Settings
Figure 11-28 Dosing Alarm Settings Menu
STOP at alarm
To set the Perox (mV) or pH peristaltic pump to STOP after a specific period of time ends and the set point hasn’t been reached, press the wheel and choose the maximum pump run time. Time can be set between 0 and 999 minutes. Move onto the next field and choose ‘STOP’.
When satisfied with settings move to Exit and press wheel.
To end procedure move cursor to ‘OK’ and press wheel to proceed to ‘Save’ request screen. Move wheel on ‘YES’ to save or ‘NO’ to discard changes.
DOSE at alarm
To set the Perox (mV) or pH peristaltic pump to continue to DOSE after a specific period of time ends and the set point hasn’t been reached, press the wheel and choose the maximum pump run time. Time can be set between 0 and 999 minutes. Move onto the next field and choose ‘DOSE’.
When satisfied with settings move to Exit and press wheel.
To end procedure move cursor to ‘OK’ and press wheel to proceed to ‘Save’ request screen. Move wheel on ‘YES’ to save or ‘NO’ to discard changes.
8.11.2 Probe Alarms
Use this menu to assign the maximum time that the pH and/or mV readings remain fixed on the same value before an alarm is raised. A stuck probe (where the reading remains on the same value for an extended time) could indicate that the probe itself is either damaged or has reached its maximum operational life.
Within this menu it is possible to set the time period after which the controller will STOP the peristaltic pumps, or DOSE will continue chemical dosing and just an alarm message (probe failure) is shown.
This function can be disabled selecting “OFF†instead of a time period in minutes. This function can be set for both or just one probe.
Parameter | Time | Action |
mV | 470min | STOP |
pH | 480min | STOP |
Table 8-7 Probe Failure Default Settings
Figure 11-29 Probe Failure Menu
E.g. To set the Perox peristaltic pump to stop after a set time of a fixed mV reading, enter the maximum time period in minutes, then press the wheel to move onto the next field and choose ‘STOP’. Time can be set between 000 and 999 minutes. When satisfied with settings move onto ‘EXIT’ and press the wheel.
To end procedure move cursor on ‘OK’ and press the wheel to proceed to ‘Save’ request screen. Move wheel onto ‘YES’ to save or ‘NO’ to discard changes.
If the pH ‘Probe Fail’ warning comes up on the screen, it is recommended that a water test is conducted by a pool professional to check the pool water chemical levels ore OK. If the pool water chemical level is OK, reset the message by entering into the menu and then exiting again. This will clear the error message. If the error message continues, further investigation should be undertaken.
Remove the probe and check for any physical damage or if any debris is attached to the end of the probe. Follow the Maintenance Guide. If these steps have been taken and the ‘Probe Fail’ Message continues the probe has possibly failed. Please contact your nearest Waterco dealer for assistance.
If the mV ‘Probe Fail’ message comes up please follow the same procedure as mentioned for pH probe fail message.
All alarms can be cancelled by entering the pass code, scrolling through the main menu and exiting.
8.12 Time & Language
Menu Use this menu to set international parameters as UNIT FORMAT (Europe IS or USA), Local Time and Date and language.
Figure 8-30 International Menu
8.12.1 Format
Use this option to use European or USA time/date format. See table for options.
EUROPE IS (International Standard) | USA |
Date (DD/MMM/YY) ) | Date (MMM/DD/YY |
Time 24h | Time AM/PM |
Table 8-8 International Menu Key
8.12.2 Time
Use this option to set local time.
8.12.3 Date
Use this option to set date.
Move to ‘EXIT’ to end changes. To end procedure move cursor to ‘OK’ and press wheel to proceed to ‘Save’ request screen. Move wheel on ‘YES’ to save or ‘NO’ to discard changes.
8.12.4 Language
Use this option to the set language of the menu. Available languages are English and French.
Figure 8-31 Setting Language
8.13 Communication Menu
Use this menu to define the communication parameter of the controller.
The Factoring of the different parameters are the following:
Parameter | Disabled Settings |
Log Menu | Disabled |
RS485 set up | Disabled |
SMS Menu | Disabled |
TcP IP | Disabled |
GPRS | Disabled |
Disabled |
8.14 Live Readings
This ‘view only’ menu shows the live value readings for the pH and ORP probes in millivolts and inputs values.
Press ‘ESC’ to exit.
The unit will not dose chemical in this mode.
Figure 8-32 Live Reading
8.15 Logged Data
To see alarm log entries as set on log menu choose “log view” on main menu.
It is required to SET DATE & TIME BEFORE TO ENABLE LOG.
IF NOT POWERED FOR ABOUT 30 DAYS THE INSTRUMENT WILL LOOSE DATE/TIME.
8.16 Hydroxypure Chemicals Controller Technical Specification
Parameter | Value |
Power Input (volts) | 220-240 |
Frequency (Hz) | 50/60 |
Degree of Protection | IP65 |
Max. Current (A) | 0.2 |
Peristaltic Pumps Capacity (Lph/gph) | 3.00/0.80 |
Max. discharge Pressure | (Kpa/Bar/PSI) 120 / 1.2 / 17.4 |
Squeeze tube Material | PS140PH |
Max Pool Size (kL / US galL) | 100 / 26,420 |
pH range | 0 to 14 |
ORP Range (mV) | 0 to 999 |
Temperature Operating Range (°C / °F) | -10 to 45 / 14 to 113 |
8.17 Chemical Controller Full Menu Structure
Figure 8-33 Full Menu Structure
The information contained may be changed at any time without prior notification or obligation.