WO2019232584A1

WO2019232584A1 - Chlorinator

Info

Publication number: WO2019232584A1
Application number: PCT/AU2019/050582
Authority: WO
Inventors: Pradeep Kumar Tandon
Original assignee: Waterco Limited
Priority date: 2018-06-06
Filing date: 2019-06-06
Publication date: 2019-12-12

Abstract

A chlorinator (100) comprising: a control unit (200); a temperature sensor (600) in communication with the control unit (200), the temperature sensor (600) being locatable in a water supply line (610) in fluid communication with a body of water; and an electrolytic salt cell (300) controlled by the control unit (200), the electrolytic salt cell (300) being in fluid communication with the water supply line (610), the electrolytic salt cell (300) being configured to electrolyse salt water to convert salt into chlorine and sodium; wherein in an operating mode, the control unit (200) is configured to control a rate of electrolysis of the electrolytic salt cell (300) dependent on water temperature data obtained by the temperature sensor (600).

Description

Chlorinator

Technical Field

[0001] The present disclosure relates to a chlorinator. In particular, the present disclosure relates to a chlorinator for use with swimming pools and spas. However, it will be appreciated by those skilled in the art that the chlorinator can be used in other water treatment applications.

Background of the Invention

[0002] There are several distinct aspects required to achieve safe swimming pool chemistry. Primarily, it is important to achieve adequate water sanitisation and water balance.

[0003] Chlorine is used to sanitise the water in many pools. Chlorine acts as a disinfectant to kill bacteria, algae and other harmful organisms. Accordingly, it is important to achieve adequate levels of sanitisation. In addition, it is desirable to avoid over chlorinating the water, as the chlorine can have a strong taste and smell which may irritate some swimmers.

[0004] Chlorine is supplied in many chemical forms such as liquid and gas. With respect to swimming pool applications, common to each of these forms of chlorine is the end active constituent which is hypochlorous acid. Hypochlorous acid provides the desired sanitisation of water to remove pathogens.

[0005] In addition to achieving the desired level of sanitisation, it is also necessary to achieve a pH balance of acidity and alkalinity. For most swimming pool applications, it is desirable to achieve a pH level of between 7.2 and 7.6. If the pH level becomes too low, for example below 7, the water becomes acidic. This can result in eye and skin irritation and corrosion of metal pump and impellor components. In contrast, if the pH level becomes too high, for example over 8, chlorine activity becomes slowed and inefficient, resulting in sub- standard sanitisation. This may result also in eye and skin irritation.

[0006] Chlorine is present in pool water in two forms:

1) Free chlorine residual - this is chlorine that has not reacted with any

contaminants and is still available to disinfect pool water and oxidise organic substances; and 2) Combined chlorine - this is "used" chlorine, that has reacted with organic substances and is no longer available to disinfect the water.

[0007] Manually adding chlorine to a swimming pool is very labour intensive. In practice, this requires the pool water to be tested regularly, typically every two days to determine the required chlorine dose.

[0008] More recently there has been a trend toward saltwater pools which utilise salt chlorinators. Saltwater pools use salt chlorinators to convert common sodium chloride crystals into chlorine gas which is soluble in water. The sodium chloride is generally added to the pool water at a dose of around 4kg per 1,000 litres.

[0009] Salt chlorinators generally use electrolysis to sanitise swimming pools, by passing salt water through an electrolytic cell which converts the salt water into chlorine and sodium.

[0010] One issue with existing salt chlorinators is that they suffer from salt and/or calcium build up on the cells. This typically requires the user to manually clean the cells regularly, for example every fortnight.

[0011] There are many factors which need to be taken into account to correctly dose chlorine in a swimming pool. For example, the volume of water to be treated and the amount the pool is used (bathing load) are both relevant. In addition, sunlight and high ambient temperatures will result in increased dissipation of chlorine through evaporation, requiring increased chlorine dosing. As such, simply running a salt chlorinator continuously is not sufficient to provide the correct dose, as various site specific factors need to be taken into consideration.

Object of the Invention

[0012] It is an object of the present invention to substantially overcome or at least ameliorate one or more of the above disadvantages, or to provide a useful alternative.

Summary of the Invention

[0013] In a first aspect, the present invention provides a chlorinator comprising:

a control unit;

a temperature sensor in communication with the control unit, the temperature sensor being beatable in a water supply line in fluid communication with a body of water; and

an electrolytic salt cell controlled by the control unit, the electrolytic salt cell being in fluid communication with the water supply line, the electrolytic salt cell being configured to electrolyse salt water to convert salt into chlorine and sodium;

wherein in an operating mode, the control unit is configured to control a rate of electrolysis of the electrolytic salt cell dependent on water temperature data obtained by the temperature sensor.

[0014] In the operating mode, the control unit is preferably configured to increase the rate of electrolysis when water temperature increases, and decrease the rate of electrolysis when water temperature decreases.

[0015] Preferably the amount of chlorine generated is increased by about 10% of a maximum chlorine dosage when water temperature increases by about 3 degrees Celsius, and the amount of chlorine generated is decreased by about 10% of a maximum chlorine dosage when water temperature decreases by about 3 degrees Celsius.

[0016] In the operating mode, a current drawn by the electrolytic salt cell is preferably generally constant, and a voltage applied to the electrolytic salt cell is variable depending on intended chlorine output.

[0017] In a salt test mode, in the event of "high salt" levels, the current drawn is preferably measured and determined by the control unit to be above a predetermined reference current, due to the salt increasing the conductivity of the water; further wherein in the salt test mode, in the event of "low salt" levels, the current drawn is measured and determined by the control unit to be below the predetermined reference current.

[0018] In the salt test mode, the control unit preferably measures and monitors the current drawn by the electrolytic salt cell and issues a warning if the current drawn varies by more than a predetermined amount relative to the reference current, thereby indicating that the salt level is determined to be excessively high or excessively low.

[0019] In the salt test mode, an alarm preferably indicates when the salt level is determined to be excessively high or excessively low, further wherein measurement of the current drawn relative to the reference current is biased such that when the water temperature increases by about +3 degrees Celsius, the reference current also increases.

[0020] In the operating mode, a user defined chlorination set-point is preferably biased to increase by 10% when the temperature sensor senses a temperature increase of 3 Degrees Celsius above 22 degrees Celsius, and the chlorination set-point is biased to decrease by 10% when the temperature sensor senses a temperature decrease of 3 Degrees Celsius below 22 Degrees Celsius.

[0021] The electrolytic salt cell further preferably comprises a flow sensor, the flow sensor being configured to determine a flow rate in the supply line and convey flow rate data to the control unit.

[0022] The chlorinator further preferably comprising a communication cable extending between the control unit and a water pump, wherein the control unit sends a stop signal to the pump in the event of a no flow signal from the flow sensor.

[0023] The electrolytic salt cell preferably includes a series of titanium electrodes with opposing charges.

[0024] The electrodes are preferably housed in a clear housing which allows visual inspection of internal salt cell plates.

[0025] The control unit is preferably configured to power the electrodes and reverse polarity after a predetermined period of time such that each cathode and each anode alternate.

[0026] In a second aspect, the present invention provides a method of treating swimming pool and/or spa water, the method including the steps of:

controlling operation of a chlorinator with a control unit, the chlorinator having an electrolytic salt cell, the electrolytic salt cell being in fluid communication with a water supply line, the electrolytic salt cell being configured to electrolyse salt water to convert salt into chlorine and sodium;

placing a temperature sensor in a water supply line in fluid communication with a body of water of the swimming pool and/or spa, the temperature sensor being in communication with the control unit, and

controlling a rate of electrolysis dependent on water temperature data obtained by the temperature sensor.

[0027] In a normal operating mode, the control unit preferably increases the rate of electrolysis when the temperature sensor senses a water temperature increase, and decrease the rate of electrolysis when the temperature senses a water temperature decrease.

[0028] The amount of chlorine generated is preferably increased by about 10% of a maximum chlorine dosage when water temperature increases by about 3 degrees Celsius, and the amount of chlorine generated is decreased by about 10% of a maximum chlorine dosage when water temperature decreases by about 3 degrees Celsius.

[0029] The control unit preferably has two primary modes of operation:

in a normal operating mode, a voltage applied to the electrolytic salt is variable and the amount of current drawn is maintained generally constant; and

in a salt test mode, the voltage applied to the electrolytic salt cell is maintained constant and the amount of current drawn is variable and is dependent on the salt content in the water.

[0030] The step of placing the temperature sensor preferably includes placement in the water flow path before a heater and after a filter.

Brief Description of the Drawings

[0031] A preferred embodiment of the invention will now be described by way of specific example with reference to the accompanying drawings, in which:

[0032] Fig. 1 is a schematic view of a swimming pool circulation system including a chlorinator according to the invention;

[0033] Fig. 2 depicts an electrolytic cell of the chlorinator according to Fig. 1;

[0034] Fig. 3 depicts a control unit for the chlorinator of Fig. 1;

[0035] Fig. 4 is a schematic view of an end portion of the electrolytic cell according to the chlorinator; and

[0036] Fig. 5 is a side view of an electrolytic salt cell of the chlorinator.

Detailed Description of the Preferred Embodiments

[0037] The chlorinator 100 includes a power pack or control unit 200 which monitors and regulates chlorine production by the electrolytic salt cell 300. The control unit 200 is connected to a 240 volt AC mains power supply. The control unit 200 also includes a back-up battery. The battery back-up ensures that user defined program settings are retained by the control unit 200 in the event of a power failure.

[0038] The chlorinator 100 includes an electrolytic salt cell 300. The salt cell 300 consists of a series of titanium electrodes 320 with opposing charges. The electrodes 320 are housed in an electrode cage 325, within a clear housing constructed from clear ultra violet stabilized acrylic, which allows external visual inspection of internal salt cell plates 340. [0039] Both anode and cathode of the chlorinator 100 are made from coated titanium plates for extra durability. Fig. 5 is a side view depicting the salt cell 300.

[0040] In operation, the control unit 200 provides electricity to the electrolytic salt cell 300 (anode and cathode) and holds an electrical potential difference between them for a designated period of time. The polarity is subsequently reversed after that period of time has expired and then the anode becomes the cathode and the cathode becomes the anode.

[0041] The electrolytic salt cell 300 is positioned in such a way as to provide a gas trap 335, as shown schematically in Fig. 2. In order to define the gas trap 335, the bottom of the electrolytic salt cell 300 is located above the top surface of the pipe from the previous piece of equipment.

[0042] The reversing of polarity or electrical potential difference acts to remove any calcium build-up, which may have been deposited onto the cathode. Accordingly, this continuous reversing of polarity provides a self-cleaning functionality which keeps the electrolytic salt cell 300 clean from calcium deposits during its operation, providing the chemical balance and flow of the pool/spa water through the electrolytic salt cell 300 is maintained within normal parameters.

[0043] In the instance that water flow is not detected by the control unit 200, the control unit 200 will shut down the pool water circulation pump 500 to protect the pump 500, by way of the communication cable 400. In this scenario, the control unit 200 also displays an alarm indicating that there is a pump 500 flow problem.

[0044] If the measured salt level in the pool water is too low or too high, the control unit 200 will reduce the output and display the corresponding alarm. In case of high salt it will record the time it was kept operating under these conditions.

[0045] The control unit 200 can control a variable speed pump 500 via the communication cable 400. In this manner, the control unit 200 enables switching on/off of the pump 500, and controlling the pump 500 speed. This function of the chlorinator 100 is only compatible with variable speed pumps 500.

[0046] The control unit 200 is connected to a temperature sensor 600 that allows the display of the pool water temperature on an LCD screen 650 of the control unit 200. The temperature sensor 600 is installed in the water flow path, in a water supply line 610, before the heater 670, and preferably immediately after the filter 700. The temperature sensor 600 provides an indication of current pool conditions, and hence provides input to calculate the amount of chlorine that may be required to sanitise the pool assuming the pH level is operating in a target band of 7.2 to 7.6.

[0047] The control unit 200 uses temperature data obtained from the temperature sensor 600 to determine what dose of chlorine to deliver, ranging from 0 to 100% of the full dose. The chlorine dosing is typically divided into 10 doses, each being 10% of the predetermined maximum dose.

[0048] For a 3 degrees Celsius water temperature rise, the required amount of chlorine production will increase by approximately 10%. The pool owner or technician must identify a suitable starting level for the chlorine dose from 10% to 100%. In operation, when a user manually changes or inputs the chlorine "Set-Point", that becomes the starting point on the scale of chlorine dosing.

[0049] Normally the pool owner or technician will test the water quality to determine the chlorine levels. This can be done at home or more commonly by testing a sample at a swimming pool supplies store. The pool owner can then determine a suitable set-point for the chlorine dose level.

[0050] From then if water temperature, as measured by the temperature sensor 600, increases by 3 degrees Celsius for example, then the production of chlorine automatically increases by 10%. In contrast, if the water temperature reduces by 3 degrees Celsius, chlorine production decreases by 10%. In this manner, the delivery of chlorine will continually and automatically be regulated based on water temperature changes, starting from the time when the initial chlorine level was defined by the user by way of the set-point.

[0051] If during operation, the chlorine set-point is changed, that becomes the new starting point.

[0052] For example, for a 9 degrees Celsius rise or fall in water temperature over time, the control unit 200 will increase/decrease the production of chlorine by +/- 30% over the same time in +/- 10% steps.

[0053] The chlorine level will top out or bottom out at 100% and 10% of the

predetermined maximum chlorine dose.

[0054] The salt cell 300 includes a series of coated titanium plates that are parallel with each other in the salt cell 300 and spaced apart from each adjacent plate by a clearance. As the water from the pool flows through the salt cell 300, the water conducts electricity from one plate to the next. There are two primary modes of operation, namely "normal operation" and "salt test mode".

Salt test mode

[0055] In the salt test mode, the voltage is maintained constant and the amount of current drawn is variable and is affected by the amount of salt present in the water, as the salt level changes the electrical conductance of the water.

[0056] In salt test mode, the DC voltage applied to the salt cell 300 is around 19-20 volts and this is maintained generally constant. During salt testing, the electrolytic salt cell 300 is operated at the constant voltage of 19-20 volts, and the control unit 200 anticipates the current that will be drawn. In the event that there is too much salt in the water, the electrolytic salt cell 300 tries to draw a large current. If the current reaches the maximum (6 amps), the control unit 200 asks what voltage is required. For example, if 15 volts is required, rather than the applied 20 volts, the control unit 200 determines that the required voltage is not high enough, so salt levels must be high. An alarm can then be issued advising the user that the salt level is too high. In contrast, if 25 volts is required, rather than the 20 volts which is applied, the control unit 200 determines that the required voltage is too high, so the salt level in the water must be low. Again, an alarm can then be issued advising the user that the salt level is too low.

[0057] Salt testing is typically conducted in the salt test mode at predefined intervals which may be daily, hourly or in a preferred embodiment, every half hour. The target salt level in the water is between 4000 ppm and 6000 ppm.

Normal operation

In normal operation, the voltage is variable and the amount of current drawn is maintained as constant.

[0058] As the electricity passes through the water between the plates 340, the electrical current converts some of the salt into chlorine. The production is chlorine is affected by factors including the quantity of dissolved salt, the size of the plates 340 and the voltage applied.

[0059] Depending on how much voltage is applied to the salt cell 300, determines the amount of chlorine generated.

[0060] During normal operation, the pool owner or technician must identify a suitable starting level for the chlorine dose from 10% to 100%. In operation, when a user manually changes or inputs the chlorine "Set-Point", that becomes the starting point on the scale of chlorine dosing.

[0061] If the water temperature increases by 3 degrees C, for example, from 22 degrees C to 25 degrees C, the control unit determines that more chlorine is required. Accordingly the control unit increases the voltage to promote a higher amount of electrolysis at the salt cell 300. The result is that the chlorine output increases from the starting %, for example 50% of maximum, to a new percentage, being 10% more, namely 60% of maximum. For every 3 degrees C, a further 10% of the maximum chlorine dose is added.

[0062] Similarly, if the water temperature decreases by 3 degrees C, for example, from 22 degrees C to 19 degrees C, the control unit determines that less chlorine is required.

Accordingly the control unit reduces the voltage to promote a lower amount of electrolysis at the salt cell 300. The result is that the chlorine output decreases from the starting %, for example 50% of maximum, to a new percentage, being 10% less, namely 40% of maximum.

[0063] The voltage applied to the electrolytic salt cell 300 is controlled by a switched mode power supply SMPS.

[0064] The electrolytic salt cell 300 uses electrolysis to convert the salt water into chlorine and sodium.

[0065] A flow sensor 800 is located in the electrolytic salt cell 300 and connected to the control unit 200 with data cable 810. The flow sensor 800 is capable of determining the flow rate of water through the electrolytic salt cell 300.

[0066] The control unit 200 has several program modes as follows:

Low Flow Condition

[0067] In the event of a "no-flow" condition being sensed by the flow sensor 800, the chlorinator 100 will increase the pump 500 speed to try to overcome any obstruction. If the "no-flow" condition is resolved, the chlorinator 100 will retain the new pump 500 speed to keep the pool pump 500 running. This feature is only enabled when a variable speed pump 500 is installed.

[0068] If after priming a "no-flow "condition is detected, the chlorinator 100 activates "Low Flow" condition detection mode automatically. [0069] The chlorinator 100 activates the pool pump 500 again, this time increasing the programmed speed to the next higher level. This occurs only when a variable speed pump 500 is running at Eco or Medium speed.

[0070] If the "Low-Flow" condition is detected again, the chlorinator 100 will issue a "no-flow" condition alarm and stop until the next timer cycle.

[0071] If there is sufficient flow, the chlorinator 100 will continue operation until the timer cycle has finished.

[0072] When the pump 500 is turned off, the "Low Flow" condition mode is deactivated until the next cycle.

Interlocking Functions

[0073] The chlorinator 100 can be programmed to activate/control multiple independent pieces of equipment together including a control valve and define the minimum required water flow for ancillary functions.

[0074] The control unit 200 includes an LCD screen 650 which displays the current time, pool temperature, pool pump 500 status, and chlorine production level (when pump 500 is on) among others. Chlorine production level is measured in percentage terms, ranging from 0% being no production, to 100% being maximum production.

User selected modes of operation

Automatic Mode (AUTO):

[0075] The AUTO mode is the default operation mode. In automatic mode, timers are operational according to pre-programmed settings.

Manual Mode (MANUAL):

[0076] Manual mode overrides the timer settings. The chlorinator 100 can only operate in STANDBY or ON mode. This mode is recommended for slave type operation, e.g. when the control unit 200 operation is directed by another device.

Winter Mode:

[0077] By selecting WINTER mode, hours of operation will be reduced to save energy during the winter months. Pressing AUTO will instantly return to standard (Summer) hours of operation. Spa Mode/Low Chlorine Output

[0078] In this mode, the chlorinator 100 will reduce the chlorine production to 10%, whilst active.

Service Mode:

[0079] When service mode is selected, the chlorinator 100 disables the electrolytic salt cell 300 chlorine production and the flow sensor 800. This allows servicing of the pool filter 700, backwashing and draining the pool.

Super-chlorination mode

[0080] In this mode, the control unit 200 will raise chorine production to 100% during a period of 24 hours to super-chlorinate or "shock" the pool. After that period the chlorinator 10 will return to its pre-set operating conditions.

Timer

[0081] The control unit 200 has a digital clock and 4 independent timers. Each of the timers can be programmed independently to have different behaviour and control different devices (outputs).

Setting the Chlorine Output

[0082] The chlorine output of the chlorinator 100 can be adjusted manually to reflect the different seasonal requirements in order to maintain satisfactory chlorine sanitisation levels. The amount of chlorine produced can be manually adjusted from 10% - 100% by accessing the CHLORINE production level menu.

[0083] When initially treating the pool water, the user starts the chlorinator, 100 and sets chlorination level to minimum output or alternatively, the user can run the pool pump only.

[0084] If it is possible, the user sets the suction line on the deep end of pool as the only suction point in the pool.

[0085] The user then adds the recommended amount of pool salt and/or Mineral Crystals in the shallow end of the pool.

[0086] The user permits the pool salt/Mineral crystals to dissolve. It is recommended to let the pool pump run for at least 6 hours to dissolve the salt completely and allow for even concentration in the pool water. [0087] The user may then set the chlorinator 100 back to normal output, for example by starting AUTO mode.

Alarms

[0088] The chlorinator 100 includes alarm signals to indicate potential problems associated with its functionality, and to protect the control unit 200 and the electrolytic cell 300. In particular, the LCD 650 of the control unit 200 will flash and indicate the correspondent situation. The following alarms may be activated.

Low Salt Level

[0089] Salt level is below the minimum allowed, please add salt to pool. The pool owner or technician is advised to consult a pool professional for advice how to increase the salt level.

High Salt Level

[0090] Salt level is above the maximum operational level. It needs to be reduced below the maximum recommended. Consult your pool professional for advice how to reduce the salt level.

Failed Pump Start (No flow detected)

[0091] If the flow sensor 800 is not detecting water flowing through the electrolytic salt cell 300 housing, the control unit 200 will stop chlorine production by stopping power to pool pump and electrolytic salt cell 300. The chlorinator 100 will repeat the start-up process twice before issuing a "No Flow alarm".

[0092]

[0093] The chlorinator 100 is designed to operate between the salt level ranges listed below:

• MINIMUM = 4000 TDS

• OPTIMUM = 5500 TDS

• MAXIMUM = 6000 TDS

[0094] Advantageously, the chlorinator 100 uses temperature sensing by way of the temperature sensor 600, which senses the temperature of swimming pool water and uses that information for low/high salt calculation where maximum threshold of the test varies according to water temperature. That is, if water temperature is low then the maximum output threshold is lowered to determine if salt condition exists.

[0095] Advantageously, temperature sensing with the temperature sensor 600 is also used to auto regulate chlorine production in salt water pools. If the temperature of the water is low, then demand of chlorine for sanitisation will be low. In contrast, if temp of water is high then demand for chlorine will be higher to achieve optimum sanitisation of water. In this manner, sensing of water temperature is advantageously used by the control unit 200 to optimise sanitisation without manual intervention.

[0096] During high temperature periods, especially on sunny days, chlorine dissipation in swimming pools is high, and chlorine demand increases to achieve an adequate level of sanitisation. Advantageously, the control unit 200 uses the temperature sensor 600 to respond to such variations in weather.

[0097] The table on the following page provides reference numbers and names for each of the components of the control unit shown in Fig. 3.

[0098] Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.

Claims

The claims defining the invention are as follows:

1. A chlorinator comprising:

a control unit;

2. The chlorinator of any one of the preceding claims, wherein in the operating mode, the control unit is configured to increase the rate of electrolysis when water temperature increases, and decrease the rate of electrolysis when water temperature decreases.

3. The chlorinator of claim 1 or 2, wherein the amount of chlorine generated is increased by about 10% of a maximum chlorine dosage when water temperature increases by about 3 degrees Celsius, and the amount of chlorine generated is decreased by about 10% of a maximum chlorine dosage when water temperature decreases by about 3 degrees Celsius.

4. The chlorinator of any one of the preceding claims, wherein in the operating mode, a current drawn by the electrolytic salt cell is generally constant, and a voltage applied to the electrolytic salt cell is variable depending on intended chlorine output.

5. The chlorinator of claim 4, wherein in a salt test mode, in the event of "high salt" levels, the current drawn is measured and determined by the control unit to be above a predetermined reference current, due to the salt increasing the conductivity of the water; further wherein in the salt test mode, in the event of "low salt" levels, the current drawn is measured and determined by the control unit to be below the predetermined reference current.

6. The chlorinator of claim 5, wherein in the salt test mode, the control unit measures and monitors the current drawn by the electrolytic salt cell and issues a warning if the current drawn varies by more than a predetermined amount relative to the reference current, thereby indicating that the salt level is determined to be excessively high or excessively low.

7. The chlorinator of claim 6, wherein in the salt test mode, an alarm indicates when the salt level is determined to be excessively high or excessively low, further wherein measurement of the current drawn relative to the reference current is biased such that when the water temperature increases by about +3 degrees Celsius, the reference current also increases.

8. The chlorinator of claim 3, wherein in the operating mode, a user defined chlorination set-point is biased to increase by 10% when the temperature sensor senses a temperature increase of 3 Degrees Celsius above 22 degrees Celsius, and the chlorination set-point is biased to decrease by 10% when the temperature sensor senses a temperature decrease of 3 Degrees Celsius below 22 Degrees Celsius.

9. The chlorinator of claim 1, wherein the electrolytic salt cell further comprises a flow sensor, the flow sensor being configured to determine a flow rate in the supply line and convey flow rate data to the control unit.

10. The chlorinator of any one of the preceding claims, further comprising a communication cable extending between the control unit and a water pump, wherein the control unit sends a stop signal to the pump in the event of a no flow signal from the flow sensor.

11. The chlorinator of any one of the preceding claims, wherein the electrolytic salt cell includes a series of titanium electrodes with opposing charges.

12. The chlorinator of claim 10, wherein the electrodes are housed in a clear housing which allows visual inspection of internal salt cell plates.

13. The chlorinator of claim 11, wherein the control unit is configured to power the electrodes and reverse polarity after a predetermined period of time such that each cathode and each anode alternate.

14. A method of treating swimming pool and/or spa water, the method including the steps of:

15. The method of claim 14, wherein in a normal operating mode, the control unit increases the rate of electrolysis when the temperature sensor senses a water temperature increase, and decrease the rate of electrolysis when the temperature senses a water temperature decrease.

16. The method of claim 15, wherein the amount of chlorine generated is increased by about 10% of a predetermined maximum chlorine dosage when water temperature increases by about 3 degrees Celsius, and the amount of chlorine generated is decreased by about 10% of the maximum chlorine dosage when water temperature decreases by about 3 degrees Celsius.

17. The method of any one of claims 14 to 16, wherein the control unit has two primary modes of operation:

18. The method of any one of claims 14 to 17, wherein the step of placing the temperature sensor includes placement in the water flow path before a heater and after a filter.