Complete guide to pool water treatment: all the parameters you need to control

Temperature is not a chemical parameter, but it has a huge influence on the treatment.

When the temperature increases, the following can also increase:

• Disinfectant demand.
• Microbiological activity.
• Algae growth.
• Bather load at certain times.
• The need for filtration.

Therefore, a treatment system that works correctly in spring may need a different configuration during the hottest days of summer.

Temperature is also a parameter that Innowater systems can take into account to manage the chlorinator’s operation.

10. Cyanuric acid: the chlorine stabilizer

Cyanuric or isocyanuric acid is mainly used to protect chlorine against degradation caused by ultraviolet radiation. Its importance depends especially on the treatment system and the type of disinfectant used.

An excessive concentration can modify the relationship between chlorine concentration and its disinfectant efficacy. Therefore, when stabilizer is used, it is not enough to measure only free chlorine; it is also important to know the cyanuric acid level.

In pools with salt electrolysis, its use and target level must be established according to the system, the facility conditions, and the applicable technical recommendations.

11. Conductivity and dissolved solids

The electrical conductivity of water is related to the quantity and nature of the dissolved ionic substances.

In a pool with salt electrolysis, the presence of salt makes the conductivity considerably higher than that of a freshwater pool. TDS (Total Dissolved Solids) represent the approximate total amount of dissolved solids.

A progressive increase can occur due to the accumulation of different substances that enter or are added to the water. Therefore, conductivity and TDS can provide complementary information on the evolution of the water, although they do not replace specific measurements of pH, chlorine, ORP, or salinity.

12. Turbidity and transparency

Correctly treated water must maintain adequate transparency.

Turbidity can appear for different reasons:

• Insufficient filtration.
• Suspended particles.
• Chemical imbalance.
• Mineral precipitation.
• Organic matter.
• Microorganism proliferation.

Therefore, when the water becomes cloudy, it is not advisable to just add more disinfectant.

You must check together: water chemistry + filtration + circulation + pool shell condition.

13. Source water quality

A parameter that is often forgotten is the composition of the water used to fill or top up the pool. This can vary, for example, depending on the source of the water and the environment (well water, canal water…)

Source water can contain different concentrations of:

• Calcium.
• Magnesium.
• Bicarbonates.
• Iron.
• Manganese.
• Other minerals.
• Dissolved salts.
• …

Therefore, two identical pools may need different treatment strategies if they use source waters with different compositions. In areas with especially hard water, for example, hardness control becomes even more important.

One of the keys to understanding water treatment is to accept that parameters do not function independently.

A simple example:

High pH

↓

Reduced chlorine effectiveness

↓

It may be necessary to increase production

↓

Higher disinfectant consumption

↓

Greater difficulty in keeping the water stable

Another example:

High hardness + high pH

↓

Higher risk of carbonate precipitation

↓

Scaling

↓

Possible deposits in the electrolytic cell

↓

Reduction in system performance

And another:

More bathers + high temperature

↓

Higher pollutant load

↓

Higher disinfectant demand

↓

Decrease in available chlorine

↓

Reduction in disinfectant capacity

↓

Need to temporarily increase production or adjust treatment

Therefore, water treatment must be understood as a system, not as a collection of independent parameters.

Summary table of the main water parameters

Not all parameters require the same measurement frequency. This frequency will depend on the type of pool, volume, use, temperature, treatment system, and applicable regulations.

As a general criterion:

Frequent control

• pH and disinfectant

These are the parameters that most directly intervene in the sanitary quality of the water and must be monitored regularly.

Periodic control

• Alkalinity
• Hardness
• Salinity
• Cyanuric acid

The frequency will depend on the characteristics of the facility and the evolution of the water.

Continuous monitoring

In automated facilities, parameters such as the following can be monitored continuously:

• pH.
• ORP.
• Free chlorine.
• Temperature.
• Flow rate.
• Salinity, depending on the system.

In professional systems, continuous control allows deviations to be detected and action to be taken before the problem is visible. The Innowater Monitor Controller, for example, is designed to continuously measure free chlorine and pH and automatically adjust the necessary dosage.

Which parameters is it worth automating for control and dosing?

In a private pool, the level of automation will depend on the owner’s needs. But there is a particularly interesting combination:

• Salt chlorination. Generates the disinfectant through electrolysis.
• Automatic pH control. Maintains the pH within the target.
• ORP control. Allows monitoring of the oxidizing capacity and regulation of disinfection.

This combination allows for a move from maintenance based on manual adjustments to a system capable of measuring, interpreting, and acting automatically.

Innowater has control and dosing systems capable of regulating pH and ORP, as well as solutions for measuring and controlling free chlorine and pH in professional facilities.

There is an important difference between measuring and controlling.

Measuring. Means knowing the state of the water at a given moment.

For example:

• pH = 7.4
• Free chlorine = X
• ORP = X mV

Controlling. Means using that information to act on the system.

For example:

• The pH increases → the controller detects the deviation → activates dosing → the pH returns to the target.
• The Redox potential decreases → the system detects a lower oxidizing capacity → adjusts disinfectant production.

This difference is the basis of water treatment automation.

Is it enough to only control the pool’s chlorine?

Categorically No. Chlorine is fundamental, but it should not be analyzed in isolation. A pool can present an apparently correct level of chlorine and yet have:

• Incorrect pH.
• Insufficient ORP.
• Unbalanced alkalinity.
• Excessive hardness.
• Filtration problems.
• Incorrect salinity.
• High organic load.

Therefore, the question: “How much chlorine does my pool have?” is important, but not enough.

The correct question is: “Is the water correctly balanced and does it have an adequate disinfection capacity?”

Does salt chlorination eliminate the need to control the water?

No. Salt chlorination automates a fundamental part of the disinfection process, but it does not eliminate the need to control water parameters. The chlorinator generates the disinfectant from salt, but water control and balance are still necessary.

In particular, parameters such as the following must continue to be controlled:

• pH.
• Disinfection.
• Salinity.
• Temperature.
• Alkalinity.
• Hardness.
• Filtration status.

Logically, automation can considerably reduce manual work, but it does not replace the technical maintenance of the facility.

What is the most important parameter of pool water?

There is no single parameter that allows you to determine on its own if the water is correctly treated. pH, free chlorine, and ORP must be understood together, while alkalinity, hardness, salinity, temperature, and other parameters help explain and maintain the system balance.

A simple way to understand it would be: The pH largely determines the conditions in which the disinfectant acts; free chlorine indicates how much disinfectant is available; and ORP provides information on the oxidizing capacity of the water. From there, the rest of the parameters help keep that system stable.

The future of water treatment: measure, control, and automate

The evolution of technology is making water treatment increasingly less dependent on manual controls. Current systems allow for the combination of:

• Sensors
• Continuous measurement
• Intelligent control
• Automatic dosing
• Salt Chlorination
• Remote monitoring

The goal is not simply to automate tasks; it is to ensure the system responds to the real needs of the water.

Automation allows for maintaining a more constant quality, reducing manual interventions, and optimizing equipment operation. Innowater develops solutions that combine salt chlorination, control, dosing, and monitoring to achieve more efficient treatment.

Pool water treatment is a complex system in which different parameters interact continuously.

pH, free chlorine, combined chlorine, ORP, alkalinity, hardness, salinity, and temperature provide different and complementary information.

Understanding this relationship allows you to avoid one of the most common errors in pool maintenance: trying to solve each problem by adding products without first knowing what is happening in the water.

The current trend is to move towards systems capable not only of measuring but also of interpreting and acting automatically.

The combination of salt chlorination, pH control, ORP, dosing, and monitoring allows for more precise, efficient, and stable water treatment.

Because the goal is not to produce more disinfectant or add more products. The goal is to keep the water in balance and provide the necessary disinfection at all times.

Frequently asked questions about pool water parameters

Which parameters should be controlled in a pool?

The main ones are pH, free chlorine, combined chlorine, ORP, alkalinity, hardness, salinity, temperature and, depending on the treatment system, cyanuric acid, conductivity, and TDS.

What is the appropriate pH for a pool?

As a general reference, it is usually worked between 7.2 and 7.6, although the appropriate range depends on the facility and the applicable regulations.

What is the difference between free chlorine and ORP?

Free chlorine indicates the amount of available disinfectant, while ORP measures the oxidizing potential of the water. They are complementary, not equivalent parameters.

Does a pool with salt chlorination need to control the pH?

Yes. Salt chlorination generates the disinfectant through electrolysis, but pH remains a fundamental parameter for treatment efficacy and water balance.

What happens if the pH is too high?

It can decrease chlorine efficacy and encourage problems such as cloudy water or scaling.

What happens if the pH is too low?

The water can become more aggressive and encourage the corrosion of certain materials and components.

What is ORP used for in a pool?

ORP provides information on the oxidizing potential of the water and can be used as a parameter to automate disinfection control.

How much salt does a pool with a salt chlorinator need?

It depends on the chlorinator model. The concentration indicated by the manufacturer must always be used. In Innowater systems, depending on the model, it usually works in the range of 4–6 g/l.

Can water parameters be automated?

Yes. There are systems capable of automatically monitoring and regulating parameters such as pH, ORP, and free chlorine, in addition to controlling chlorine production and dosing.

Is it better to measure water manually or automate it?

Manual measurement is still important, especially for verifications and maintenance, but automation allows for much more continuous control and reacting sooner to deviations.