For 32 years, the voice of the pool and spa service professional.

Automated pool operation changing the role of service techs

By Doug Walsh

The day-to-day tasks of the pool and spa service technician have certainly undergone changes over the years. Few would argue that it takes more than a 4-pack of chlorine and a T-pole to maintain a pool at today’s standards.

From variable-speed pumps to centralized automation controllers, modern pool technology offers precise control for both customer and the service personnel — along with an array of new responsibilities.

While devices on the cutting edge of automation are designed to keep water sanitized and algae-free with a minimum of human intervention, many technicians shy away from their use. But they do so at their own peril. Only by becoming educated on these products can service firms take advantage of a wide range of new profit opportunities.
Today’s automatic systems allow pool owner’s to control all outdoor pool, spa, water feature, lighting, sprinkling and safety functions from an onsite or in-house control panel or remotely from a laptop computer or even their cell phone.

 And service professionals — sitting at a remote location — can monitor several pools at once, staying on top of chemical balance or equipment functions without physically checking the pools unless alerted to do so by their computer. Warning bells on a cell phone or an email can caution techs about a chemical imbalance or an equipment issue. 

In fact, the latest automated systems incorporate live cameras and uploadable programs that allow a service tech to fix many electronic problems with the push of a few buttons. Rather than driving to the jobsite, service technicians can turn on the cameras, look at the program and see where the problem is. Often they can fix the problem, check the results on-camera, and resolve the entire issue from the comfort of their office.

In fact, when this tech does show up at the customer’s pool, it’s often only to handle a situation that the customer has no knowledge about, because the automatic monitoring system flagged the situation before it became a problem.

 As technology evolves, mobile drives new automation standards

Whether it’s automatic cleaning, system operation, chemical monitoring or generation, automated pool applications are increasingly changing the work being performed by service professionals.

Today’s automated systems include built-in microprocessors that can record data about the pool’s design, monitor filtering cycles, backwashing, heating and lighting, water features, entertainment centers and monitor and adjust water chemistry. 

Modern control units can operate more than 30 individual tasks from a single control panel, and are often upgraded to completely integrate all home automation system that includes audio, security, climate, irrigation and more.  And while it may take an engineering degree to design these systems, the control panel operation is fairly simple.

It was actually a rather simple innovation that led to the development of the automation industry in swimming pools. The air switch — a simple button that pushes air through a plastic tube to expand a diaphragm that can in turn throw an electric switch — first allowed bathers to remotely control spa functions while protecting them from electrical current.

Later, the 4-function switch was developed, which uses micro-switches and a ratchet-and-cam configuration to control different piece of equipment. Modern developments have allowed for increasingly smaller switches that control more and more functions.  

The multiport valve is the device that allows the pool and spa to be operated off the same equipment. With these devices, water flow can be directed and reversed.  When the multiport was linked with an actuator motor, these operations could be performed with a flip of a switch. 

 The signal to activate the actuator can be sent by remote control by the operator. But that doesn’t make it completely automatic. It can be set to run automatically in either by a time function, set by time clock to switch on or off at a given, pre-set time, or, as in the case of an automatic backwash valve, it can be a function of the pressure differential on the filter.

From a water chemistry point of view, it was the development of ORP-based technology that allowed for automation to proceed. ORP stands for Oxidation Reduction Potential, a measurement of the water’s ability to oxidize contaminants. Oxidizers such as chlorine and bromine work by taking electrons from other substances. 

Soon, chemical controllers, working in combination with a pH and other sensors, were developed that could activate feeders or other dispensers of pool chemicals only when the chemicals are required.  Some units contain flow sensors that monitor the flow rate across the ORP and pH sensors.  This allows the unit to deactivate the automated chemical feed when the filtration system is off or low circulation is detected. 

Chemical automation takes all of the guesswork out of maintaining proper chemical levels.  Because the controller continuously measures chemical levels, the pool is always receiving chemicals consistent with the water’s demand. And on-site chemical generation devices are taking away the task of even transporting chemicals to the customer’s pool by “manufacturing” all the necessary sanitizer and balancing chemicals poolside.

 With all the basics in place, it was the development of wireless radio signals that now allow for remote operation of these functions and many more from a control panel placed conveniently inside a customer’s home.

Leap forward to today and we know that our world increasingly can be described in one word: mobile. Mobile phones and apps available for them are literally running our lives. And in increasing numbers, they are running our pools, too.

 Makers of mobile apps are working hand in hand with major pool and spa manufactures to deliver an interactive pool and spa control experience that makes in easier than ever to turn the pool heater off and on, adjust the spa temperature, crank the jets and adjust the chemistry — all from iOS and Android smart devices.

 One thing is certain: If pool and spa companies are not gaining knowledge and offering these mobile-ready systems to their upscale customers, it is likely that their competitors are. The following stories a complete rundown of automatic technology designed for the pool and spa industry.

By Marcell Dibrell

Automated pool care service may just be the height of customer service in the pool and spa industry. 

Not only are pool professionals able to control just about every aspect of a customer’s pool from the sanitizing schedule to the circulation system, they can also do so without being physically present because the most recent advances have put all of these functions on the Internet.  

Water chemistry and circulation as well as heating, lighting and other water features can all be controlled with the help of computer-chip technology that sends electronic signals to microswitching devices, multiport valves and actuators.

The actuator is controlled by a remote device that sends a signal to a pair of microswitches that then drive cam shafts to turn the valves to an open or closed position.

To make these systems completely automatic, they can be set to run on a time clock to switch on or off at a preset time every day. 

Today, the systems have been developed to allow radio signals to drive the operation remotely, from inside the home, and via the Internet.

And a key element in full chemical automation requires that the system have self diagnostic tools at hand. 

ORP probes and pH sensors have made it possible for the pools to both test and dose themselves as needed. 

As we launch into a discussion about automation, it seems like a good idea to make a distinction between the words automation and automatic.  Automatic devices rely on an external input, like a person, or timer, to turn them on or off.  Automated devices, on the other hand, are regulated by an internal result that is compared to a target value that is preset or pre-programmed. 

For example, indoor climate control, pool temperature control, and certain kinds of chemical feeders and generators are automated devices, while most filter pumps and pool cleaners, set on a timer, are automatic. 

The use of automated chemical feeders has become more prevalent with the growth of public health concerns.  Automated chemical feeders assure consistent sanitary conditions, which reduces the possibility for disease occurrence.

And because of these growing health concerns some states now require the use of an automatic chemical feeding system, particularly for public pools and spas.  To name just a few, this is true of many California and Texas counties, as well as the states of Montana, North Carolina, Ohio, and Vermont, and the list is growing.

Automation, in the pool industry, refers to three general areas of study:  Automatic cleaning systems, automatic system operation, and automatic chemical monitoring/feeding/generation. 

The topic of automatic pool cleaners was covered in detail in the Oct. 31 edition in “An in-depth comparison of today’s pool cleaners,” and there is little doubt of the value of those devices.  This edition will focus on the key element relevant to the pool and spa professional:  automatic chemical monitoring, feeding, and generation.

One of the best ways to provide consistently high quality water is to automate chemical process.  

That is because the two most common changing chemical parameters in a pool are the pH and the concentration of the disinfectant. 

Proper water balance will help to buffer against wild fluctuations in pH.  However, different disinfectants have a different pH, and depending on the amounts used, as well as the bather load and other conditions, the pH in a pool must be constantly monitored and adjusted accordingly.

Also dependent on bather load and other environmental conditions, the concentration of sanitizer must be monitored and adjusted.

For many pools, these tasks are accomplished manually, but some pools require near constant testing and chemical adjustments to keep them in line.  High maintenance pools such as these are ideal candidates for automated chemical feeders. 

Automated feeder control systems utilize chemical sensors or probes to measure the water chemistry and controllers to activate pumps to feed disinfectant or pH adjusting chemicals.  The controller will then turn off the pump when the chemical feed is completed.  The following articles will examine how this technology works.

ORP for Testing Sanitizers

One of the most commonly used sensors for sanitizer activity in a chemical controller uses an ORP probe.  ORP stands for oxidation reduction potential and is also sometimes called redox. 

ORP values describe the ability of the sanitizer in the water to oxidize organic contaminants, with higher numbers representing better oxidative capacity.  Using ORP measurements is one way to determine how active a given sanitizer is in water.   ORP values are not linearly related to the actual free sanitizer concentrations but can be correlated to them if the pH is known.  The graph shows the correlation between ORP and free chlorine as a function of pH.

It can be seen that for a given concentration of chlorine, as the pH rises, the ORP decreases which is the oxidative strength.  It is well understood that more chlorine is in its killing form as hypochlorous acid, at lower pH, and ORP values correlate to this fact.

The graph also shows that at a given pH, the higher the ORP value, the greater the sanitizer concentration.  Therefore, ORP is an indirect way of assessing sanitizer concentrations. 

Measuring ORP requires two electrodes: an ORP electrode and a reference electrode.

In practice, ORP is measured by placing the ORP electrode in a solution containing an oxidizer, such as chlorine.  The ORP electrode is made of an inert metal such as platinum or gold that has the ability to either give up or accept electrons.  If it gives up electrons, it has become oxidized. If it accepts electrons, it is reduced. 

Relative to the ORP electrode, most sanitizers are oxidizing agents, which means that they will take the electrode’s electrons.

The other component is the reference electrode.  This is frequently made of silver in a silver chloride solution, and it supplies a constant stable output for comparison with the ORP measurement.  Thus, if the difference between the values of the ORP electrode and reference electrode is positive, then the ORP probe has been oxidized by an oxidizing agent, while if the difference between the values is negative, the ORP probe has been reduced by a reducing agent.

The minimum desired voltage between the electrodes according to most standards is 650 mV, because values below this are not very effective at killing or inactivating pathogens.  Today, more and more experts recommend 750 mV as the minimum.

Oxidation suffers when ORP drops, and is a useful way to determine the killing capacity of the sanitizer in question.  In automated chemical feeders, when the ORP value falls below the set ORP requirement, more sanitizer will be added to bring the value back to the minimum requirement

While using ORP values is useful for measuring the oxidative power of chlorine, there are some issues that complicate the measurement.  As previously stated, pH plays a big role in how a given concentration of chlorine will register in terms of ORP.

Another factor that changes the ORP values measured for a given concentration of chlorine is the cyanuric acid concentration, although it is not clear to what extent this is meaningful.  See the accompanying story. 

There is no doubt that cyanuric acid lowers the ORP values for a given starting concentration of chlorine. 

It does this in two ways.

First, because cyanuric acid reacts with chlorine, it removes some hypochlorous acid from solution.  Because hypochlorous acid is an oxidizer, the oxidative strength will obviously go down.

Second, when using cyanuric acid, a thin invisible film tends to form on the surfaces of the probes, and they must be cleaned regularly or the accuracy and response time will be reduced. 

What is the effect of Cyanuric Acid?

One factor that changes the ORP values measured for a given concentration of chlorine is the cyanuric acid concentration.  Many studies have shown that cyanuric acid lowers the ORP values for a given starting concentration of chlorine. 

This was explored in an article called “Cyanurics~ Benefactor or Bomb,” presented by Kent Williams of the Professional Pool Operators of America.  It was shown that even with a high 4 parts per million chlorine concentration, in the presence of 70 ppm cyanuric acid, the ORP was measured at the low value of 640 mv. 

Studies have also shown that lower ORP values results in less germicidal ability; therefore, lots of experts recommend capping the concentration cyanuric acid to no greater than 70 ppm. 

While numerous studies in pure water have shown a definitive correlation on high cyanuric acid concentrations with lowered germicidal chlorine activity, one criticism of these studies is that they are mostly not conducted in pool water, where other substances in the pool water can affect the kill rates of chlorine.

This was pointed out at in presentation at the 2004 International Pool & Spa Expo in 2004, by Thomas Kuechler, who noted that whether or not cyanuric acid is in a pool, kill rates are longer in pool water than in pure water.  He hypothesized those substances such as ammonia, amines, amino acids and creatinine affects kill rates and that sometimes cyanuric acid plays a role in the kill rates for some strains of bacteria while in other strains it does not. 

In other words, many of the studies on actual pools seem to present conflicting data. 

Kuecher maintains that an appropriate free chlorine concentration will control both bacteria and algae, regardless of the cyanuric acid concentration (even well above 100 ppm cyanuric acid) and recommends 1 ppm to control bacteria, and 3 ppm to control algae.

But while no one seems to dispute that cyanuric acid lowers the ORP values in a pool, some believe that the effect has been overstated. 

For example, a presentation entitled “The impact of Cyanuric Acid on Pool and Spa Water, ORP, and Amperometric Controller Probes,” presented by Thomas Lachocki, Ph.D, shows data that implies that the drastic reduction in ORP values for various cyanuric acid concentrations may have more to do with dirty ORP probes.  At comparable values of 4.5 ppm chlorine and 70 ppm cyanuric acid, the probes gave ORP values of almost 750 mV after they had been cleaned.

Considering all of the conflicting data, presented here, it seems apparent that more research should be conducted in this area.  

Amperometric Probe

Relatively new to the North American pool and spa market, amperometric probes, while more expensive, have some distinct advantages over ORP probes. 

These probes measure the amount of sanitizer present by applying a voltage between two electrodes and measuring the current flow between them.  At the working electrode, the cathode, any hypochlorous acid present will be reduced to a chloride ion.  The current that flows as the result of this reduction is proportional to the amount of hypochlorous acid present.

One of the advantages of amperometric measurement is that because the current flow is proportional to the chlorine present, it has a linear response to changes in the chlorine concentration.  This is as opposed to the logarithmic change in potential that is measured in ORP.

Another advantage is that the measurement is faster than ORP. 

Also, the electrodes have a fine membrane that covers the surface of the probe which protects the surfaces from getting dirty, as happens with ORP sensors.

pH Probes

The single most important parameter for the ability of chlorine to function in water is pH.  At high pH values, hypochlorous acid has dissociated or broken down into its less effective components, while at low pH values, hypochlorous acid is in its active form.  It is therefore important that automated controllers consistently measure and adjust pH to the appropriate level. 

Electronic meters or pH meters are routinely used to determine pH.  The meters are accurate and compensate for temperature extremes (like in spas).  They operate in a similar fashion to voltmeters, in that they are in fact measuring a chemical potential, and then converting it to a concentration measurement.

In a manner similar to how ORP is measured, two electrodes are necessary for measuring pH: an indicating electrode, and a reference electrode.  Most devices today use a combination electrode with both of the electrodes in one body. 

In one configuration, there is a reference electrode, composed of silver with silver chloride at its interface.  This silver electrode is immersed in a solution of potassium chloride.  This gives the reference electrode a fixed electrical potential. 

The indicating electrode is also a silver wire coated with silver chloride.  It is immersed in a buffer solution of pH 7.  It is surrounded by semi-permeable glass membrane that allows the flow of hydrogen ions in its outermost layers. 

This sets up an electrical potential difference between the solution inside the glass, and the solution outside the glass of unknown pH.  The size of the potential difference depends on the concentration of hydrogen ion inside the glass relative to those outside the glass. 

The difference in potentials between the reference electrode and indicator electrode gives the millivolt signal that is proportional to the pH. 

The whole set up is connected to electronics that convert this potential difference into a pH value, where a low pH is indicative of a higher amount of hydrogen ions outside the glass, and a high pH is related to a low amount of hydrogen ions outside the glass.

Chemical Feeders

Chemical feeders can represent a huge time saver for the average pool owner, and they can definitely help save the chemistry of the pool, but they are not trouble free.  The feeders develop clogs, the chemical container run dry, and certain parts will require replacement.   

There are several different types of chemical feeders which fall into four basic categories: liquid, dry, gas, and chlorine generators. 

Some of these feeders use electrical timers and are thus semi-automatic.  The chemical feeders can be totally automatic, wired to a controller that opens and closes valves dependant on the chemical needs of the pool

-Liquid (diaphragm, peristaltic, venture)

Liquid chemicals are fed into pools using one of three types of feeders:  peristaltic, diaphragm, or venturi. 

Peristaltic feeders have a motor driven roller assembly that squeezes a flexible tube.  A constant volume of liquid is released as the rollers move.  One reason for their popularity is that because they have few moving parts, they are durable.  However, care should be taken with respect to their location relative to the chemicals. 

Specifically, the pumps shouldn’t be mounted directly over chemicals because the fumes can damage the equipment.

Furthermore, the pumps shouldn’t be mounted over other equipment in case a leak develops.

Regular maintenance on peristaltic pumps includes cleaning and/or replacing the feed lines, which tend to get clogged and shorten the life expectancy of the pump.

Diaphragm pumps have a casing that encloses the diaphragm, whose motion is controlled by a rotating cam.  When the diaphragm moves out, a vacuum is produced that sucks liquid through the first check valve.  After the pump is full of liquid, the check valve closes to hold the liquid inside.  When the diaphragm moves in it squeezes the liquid into a feed line, injecting it into the circulation line. 

Maintenance of diaphragm pumps includes ensuring that the check valves, which are spring loaded, are in good working order.  These can become clogged and stop operating properly.  To avoid this, the diaphragm should be flushed once a week.

A venturi system eliminates the need for metering pumps, instead creating a vacuum that pulls the liquid through a large venture into the water flow.  Since the liquid is infused into the water, it mixes quickly, and chemical readings can also be adjusted quickly. 

In terms of maintenance, these units should be cleaned every few weeks.

-Dry and Erosion

An erosion feeder does exactly what it sounds like:  gradually erodes away a solid chemical.  For erosion feeders this is an effective way to sanitize the pool if the product is soluble, but also depends on the flow rate of the water through the device as well as the surface area of the chemicals.

The operational principle is simple.  The chemical is placed in the feeder and the container is capped.  Water flows through the feeder and the flow erodes and dissolves the chemicals.  Its important to monitor the water flow because it is the flow rate that determines the concentration of chemical output.  Newer systems have flow regulating valves and some installations require the use of a flow meter.

There are a few different specific types of erosion feeders that can be employed.

Pressure erosion feeders, mounted after the pump, use the pump’s pressure to get water flow.  They are equipped with a bleed valve, as is any feeder designed to operate under pressure.  This ensures the safety of the pool operator, who should take care to determine that there is no pressure inside the feeder prior to opening. 

Pressure differential erosion feeders, installed downstream from the pump, bring the water in on the pressure side of the pump, and let it out farther down the line, where the pressure is much less.  It is that difference in pressure that moves the water.  These systems sometimes use a venture loop to create a vacuum, a booster pump, or a throttling valve to return the water into the line.

Spray erosion feeders are used with calcium hypochlorite.  They function as their name implies, spraying the chemical with water rather than submerging it.  Care should be taken with calcium hypochlorite, whose high pH and calcium content will cause scale formation unless preventative steps are taken.  And for the same reason, it is a good idea that the pipes that transport the water from the feeder have large diameters and are regularly cleaned.     

Consult the installation manuals for proper sizing of these feeders, as well as plumbing instructions and connections to controllers. 

-Chlorine Generation/Ozone/UV

Chlorine generation

Some sanitizing systems that are particularly suitable for automation include salt water chlorine generators, ozone generators, and ultraviolet systems.

Salt water chlorine generators are one of the most popular ways to sanitize residential pools because they create free chlorine in the water, eliminating the need to store, transport and handle this chemical. 

Usually installed in-line, around 3,500 ppm sodium chloride is added to the pool, and the circulation system forces the water through a cell containing plates that convert the chloride ion in the salt into free chlorine via electrolysis. 

Chlorine generation also produces a strong base, sodium hydroxide, which will cause the pH in a salt water pool to rise over time, and an acid must be added to counter this. 

Chlorine generation systems adapt easily to automation, but service professionals should still take care to monitor traditional chemical parameters when using chlorine generators. 

Free chlorine should be tested weekly, and the ideal range of 1 to 3 ppm maintained.  And prior to handling pH, alkalinity should be adjusted to within 80 to 120 ppm, adding sodium bicarbonate to increase the levels, and acid to decrease levels.

Slightly higher stabilizer concentrations are usually recommended for salt pools — within 60 to 80 parts per million.  Calcium levels should run between 200 and 400 ppm.

If cyanuric acid or calcium levels get too high, partial draining and refilling will be necessary.

Look for more information about chlorine generation in the May edition that focuses on this topic.

-gas feeders

Many automated systems use gas feeders to control the pH and much less frequently to introduce chlorine so this discussion will be limited to pH adjustment.

While it is obvious that acid can be used to control elevated pH, recently it has become popular to use carbon dioxide as an alternative method.  Using carbon dioxide gas is useful particularly in the case of saltwater chlorine-generated pools, which require frequent pH adjustment.

When carbon dioxide is introduced into water, it produces carbonic acid, a weak acid that lowers the pH.  It does have the tendency to increase the total alkalinity, so that level should also be monitored.

Carbon dioxide is delivered to the pool via high pressure tanks.  It must be released in a controlled manner and therefore requires a release regulator. 

It is particularly well suited to automation; the regulator is connected to the automated feeder control system.  If the pH probe senses elevated values, the controller system “tells” a solenoid to open up the gas, automatically adjusting the chemistry.

 Ozone and UV systems

Ozone systems are also easily adapted to automation, but to maximize its work value, it must be installed into the circulation system in an effective manner.

This is generally considered best accomplished using a venturi injection system.  The placement of the ozone injection should be downstream from the operating equipment but before the injection point of the disinfectant.

Some installations use a booster pump, introducing the ozone into a circulation side stream. Taken from the main circulation stream after the filter, the ozone is applied to the side stream and then the ozonated water is returned to the main stream prior to the injection of sanitizer.

For even longer ozone contact times, some systems also have a contact column.  This is a device that maximizes mixing the ozone with the water for enhanced contact times.

Ozone can be created via corona discharge, producing a high quantity of ozone, or UV ozone generation, which produces less ozone, and is also less expensive.

Ultraviolet light also can be used independent of ozone generation to help disinfect water.  UV light is a disinfectant, and it both kills and inactivates pathogens such as bacteria, viruses and parasites by damaging DNA.  It is considered a supplemental oxidizer and must be used in conjunction with an additional sanitizer that can provide a residual. 

UV systems are installed after the filter with a flow switch that can shut down the system if the water flow is interrupted. 

In addition to deactivating pathogens, UV is capable of eliminating chloramines.  Nitrogenous substances introduced into the water from multiple sources that come into contact with chlorine form numerous disinfection by-products such as chloramines, trihalomethanes, and more. 

Different lamp pressures are available that change the power density achieved by the system. Medium-pressure UV lamps have a higher power density than low-pressure lamps, which have been demonstrated to efficiently control the accumulation of chloramines.  Low-pressure UV photolysis is much less efficient, and neither pressure has any effect on trihalomethanes

For a UV unit to properly perform its function, the light must be absorbed by microorganisms, passing effectively through the water.  Accumulation of chemical or biological films of the surface of the lamps, or dissolved matter and turbidity can prevent this.  Therefore, proper water chemistry will require monitoring.

The UV systems need regular service, and the manufacturer’s maintenance guidelines should be consulted.  However, routine service once or twice a year includes draining and inspection of the UV chamber.

Look for more information on ozone and UV systems in the May issue on sanitizers and alternatives.

Trouble-shooting Controllers, Metering Pumps, and Feeders

Automated chemical feeders can help save time, but like everything else, need attention, maintenance, and occasional trouble-shooting.  Routine maintenance of chemical feeders can prolong their lifetime and avoid certain problems that can result from neglect. 

For example, to avoid leaks, it is important to regularly clean the connections and tubes on a regular basis. 

Similarly, it is a good idea to make a habit of inspecting and replacing o-rings, gaskets, and connection points as needed. 

The controllers, feeders, and fill levels should also be routinely checked to ensure that chemicals are actually entering the water.

Furthermore, the filter pressure and water flow must also be maintained because if water is not flowing to the controller or if the flow pressure is inadequate, sometimes the controller will not display any values.

To make certain that the controller readings are accurate, the water must be regularly balanced, and the controller readings checked often. 

There are many reasons that can explain why feeders stop dispensing chemicals.  Feeder lines and injection points can become clogged.  This can become dangerous if high concentrations of gases build up in the lines or in the pipe work if the water flow gets low.  Chlorine gas is deadly in high enough concentrations and extreme care should be taken if this is the case. 

For the same reason, a chemical gas leak can also lead to a potentially dangerous situation.  In the case of a leak, open all doors to ventilate the room before entering and consider wearing a respirator if one is available. 

It is good practice to check regularly for leaks.  To check for carbon dioxide, a mild soap solution can be applied around all connections as well as along the tubing, while watching for bubbling.  To check for a chlorine gas leak, a mist of ammonia sprayed near the tanks will result in the immediate formation of chloramines, indicated by a white mist, if a leak exists.

Routine maintenance steps can help to prevent plenty of problems.  However, certain problems may occur even with the best of intentions.

For example, there are numerous reasons that could contribute to a chemical feeder malfunctioning resulting in the chemical agent not entering the water.  The reason could be as obvious as the metering pump or controller is not plugged in, or the more complicated situation in which the controller is not calibrated correctly.  

Clogged injection point or feeder lines will also mean that chemicals can’t enter the water.  Insufficient water flow, perhaps caused by a filter that needs servicing can also cause feeders to malfunction. 

Chemicals may not be dispensed because there is a leak in the tubing, or the tubing connections are loose, or because a gasket or O-ring needs to be replaced.

Finally, be sure to check the chemical tank, which could be empty.  

It is generally not recommended to calibrate automate controllers very often; many service technicians will do so only once a year.  If the controller pH readings are off, or if ORP fluctuates, this is sometimes caused by dirty probes.  This may be necessary more often if cyanuric acid is in the water, depositing a thin film on the probes.

Most manufacturers include probe cleaning instructions in their manuals.  For easy reference, it is useful to keep these instructions near the probes. 

In general, probe cleaning begins with turning off the power to the controller.  The probes should then be removed from the flow chamber and gently scrubbed using a mild detergent and a soft brush.  The probes can then be reinstalled and the power returned.

Automatic ORP cleaners are also available for probe cleaning.  Some controllers are equipped with an auto-flush sequence, which switches on an acid pump for a short time that will automatically clean the probes.

After cleaning the probes, it is not abnormal for the ORP probe to read a little high for several hours.  While waiting for the probe to settle down, it will be necessary to manually test and dose the water.  High ORP readings will prevent the feeder from turning on even if the actual chemical levels are quite low.

To get accurate readings from the probes, it is important that they are installed appropriately.  The probes should be located before the chemical feeders so that they are not damaged by excessive chemical concentrations as well as giving false readings. 

Temperature affects pH readings so probes should be placed before the heater and out of sunlight. 

Finally, to prevent particulate accumulation on probe surfaces, they should benefit from clean water by locating them after the filter.

Calibrating an Automatic Controller

Calibration is defined as checking the accuracy and adjusting the precision of an instrument according to the comparison with a standard.  In most cases, calibrating automatic controllers should be done rarely, because the act of calibration often, in fact, leads to miscalibration.

This is because many of the tests rely on using color to determine the result.  Without a colorimeter, the results can be somewhat subjective, especially in the case of changing light conditions.  The results can also vary from person to person depending on vision precision.

Also, chlorine residuals will affect pH tests and lead to inaccurate results.

Finally, water use and organic contamination leads to changing chlorine demand and thus chlorine tests can be unreliable if not done at the proper time.

Generally speaking, stable electrodes should not need frequent standardization, the practice of manually overriding the probes results by entering different values for chlorine concentration or pH from a separate test.

If calibration of a precise instrument is required, then it should obviously be done by using the best test kit possible. 

To avoid changing chlorine demand conditions, the test should be conducted prior to any bather load and with stable temperature conditions.

Because ORP is calibrated best at low chlorine concentrations, the test should be performed when the chlorine residual is between 0.5 and 1.0 ppm.

Following are a few examples from the Service Industry News Show 'N' Tell section that feature new products designed to make pool and spa operation fully automated:  

Control4 Corp certifies OmniLogic with SDDP tech

OmniLogic, the new backyard control system from Hayward Pool Products of Elizabeth, N.J., is the first pool controller featuring Control4 Simple Device Discovery Protocol (SDDP) technology to be certified by Control4 Corp. for seamless integration with its home automation systems.

The new integration option utilizes the newly released pool and spa user interface from Control4. With the purchase of the Hayward OmniLogic pool controller, dealers can expand the capabilities of new and existing Control4 projects to control swimming pool and spa heaters, filter pumps, water features and more. OmniLogic can be controlled from any Control4 interface including apps for iPhone, iPad and Android.

Control4 users can now manage the most important aspects of the backyard from the same interface as the rest of their home and property.

With the new OmniLogic backyard control system, Control4 smart home owners can enjoy touch-of-a-button access to independent temperature controls for the pool and spa as well as control over spa jets, pool lights and even system filter pumps.

For more information, contact Hayward Pool Products, Dept. SI, 620 Division St., Elizabeth, NJ., 07207. Telephone 800-657-2287. Or visit the company Online at


iAquaLink 2.0 simplifies mobile pool operations

Zodiac Pool Systems of Vista, Calif., manufacturer of iAquaLink, recent winner of the People’s Choice “Best Connected Home Product” Internet of Things (IoT) award, introduces iAquaLink 2.0 offering simplified installation of mobile pool control.

This newest version eliminates the need for PCs, cables and software downloads during installation and is compatible with all residential WiFi routers. iAquaLink can be connected via a WiFi hotspot method using a smartphone or table computer or by a WPS method using a WPS-enabled router.

Zodia. is working with companies such as URC and Crestron to integrate AquaLink pool control systems via iAquaLink wirelessly into 2-way control modules that support every home automation category, including pool and spa,security, locks, lighting, surveillance, climate and more.

The technology also provides efficient pool management tools, making it possible to monitor, diagnose and even reconfigure clients’ pools remotely from a single app.

The system can access the exact customized labeling that has been set up by the pool pro, maintain-
ing consistency and end-user familiarity between the OEM and URC interfaces so that labels are all the same.

 iAquaLink apps are simple and intuitive, and downloads of the app and its ongoing Cloud service are free. Upgrades are available to support every AquaLink control system.

Zodiac is a leading global manufacturer of differentiated pool and spa products. The company's rich heritage of innovation excellence has caused the development of some of the world’s leading products.

Zodiac Pool Systems. Dept. SI, 2620 Commerce Way, Vista, CA 92081. Telephone 800-822-7933. Or visit the company Online at

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