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Types of Pool Water: Understanding Your Pool’s Chemistry

Types of Pool Water: Understanding Your Pool's Chemistry

Do you have a swimming pool or are looking at installing one? Well, it’s important to understand the chemistry of pool water to maintain a clean and safe swimming environment. In this blog, we explore the different types of pool water and their pros and cons, as well as how to effectively manage their chemical composition. From chlorine levels to pH balance, we cover everything you need to know to keep your pool water crystal clear.

The Importance of Pool Water Chemistry

Maintaining the proper chemistry of your swimming pool water is crucial because its chemical composition directly impacts the health of swimmers and the longevity of pool equipment and surfaces. 

Unbalanced pool water can lead to a range of issues, including skin and eye irritation for swimmers, the growth of algae and harmful bacteria causing health issues, and corrosion of pool equipment. By keeping a close eye on the chemical levels in your pool water, you can ensure a safe and enjoyable swimming experience for everyone.

Introduction to the Types of Pool Water

Person cleaning and chlorinating the pool on a hot summer afternoon

Chlorinated Pools

Chlorinated pools are the most common type of swimming pool due to their cost-efficiency and effective sanitisation. As the name suggests, these pools are kept clean and clear by adding chlorine to the water in either a liquid, granular, or tablet form.

When chlorine is added to water, it reacts to form hypochlorous acid (HOCI) and hypochlorite ion (OCI-), both of which effectively kill bacteria and other harmful contaminants such as dirt, oils, and sweat introduced by swimmers.

Saltwater Pools

Saltwater pools offer a popular alternative to traditional chlorinated swimming pools. They provide a more natural and often more comfortable swimming experience. 

Saltwater pools use a salt chlorine generator to convert sodium chloride (salt) into HOCI (chlorine), which sanitises the pool. The salt level in a saltwater pool is much lower than that of seawater, meaning it’s gentler on the skin and the eyes. The typical salt concentration in a saltwater pool is about 3000 to 5000 parts per million (ppm) compared to the ocean’s salt concentration of about 35,000 ppm.

Mineral Pools

Mineral pools represent an innovative approach to pool water sanitation, offering a more natural alternative to chlorine or saltwater pools. Mineral pools use a combination of minerals like magnesium, silver, and copper to purify pool water which enhances the water quality while providing health and wellness benefits to swimmers.

Mineral pool systems often work alongside a reduced level of chlorine or a chlorine generator to make sure the pool remains sanitised without heavily relying on traditional chemicals.

Pros and Cons of Each Pool Water Type

Pros and Cons of Each Pool Water Type

If you’re looking to install a pool and are deciding on a pool water type, be sure to consider things like maintenance, cost, swimmer comfort, and potential health concerns. Each type comes with its benefits and drawbacks, and the best choice will depend on your needs and preferences.

Chlorinated Pools

Pros

  • Effective sanitisation: Chlorine is highly effective at killing a large range of pathogens to make sure the water remains safe for swimmers.
  • Cost effective: Compared to other sanitisation methods, chlorine is relatively inexpensive and widely available, which makes it the most cost-effective option for pool owners.
  • Ease of maintenance: Maintaining a chlorinated pool is fairly straight forward. Routine tasks, such as testing the water and adjusting chlorine levels, are easy to perform with products readily available and most pool supply stores.
  • Algae control: Algae growth causes discolouration, creates slippery surfaces and clogs filtration systems. Chlorine effectively kills algae cells which prevents algae from growing.

Cons

  • Harsh on skin, hair and clothing: High levels of chlorine can cause skin and eye irritation for some swimmers. It can also cause swimwear and fabrics to fade or whiten in colour.
  • Regular testing: While chlorine itself is easy to use, maintaining the right chemical balance in the pool requires regular testing and adjustment which can be time consuming.
  • Health concerns: Chlorine is a hazardous chemical that requires careful handling and storage. Mishandling can lead to health risks, including respiratory issues or skin burns.
  • Environmental impact: Chlorine and its by-products can affect air quality around indoor pools, are toxic to aquatic life, and can damage the environment if discharged irresponsibly.

Saltwater Pools

Pros

  • Cost effective over time: While the initial setup cost is higher, the ongoing costs can be lower as there’s less of a need to purchase chlorine and other chemicals regularly.
  • Easy maintenance: Saltwater pools are considered less time consuming than chlorinated pools as the salt chlorine generator automates certain processes. However, it does need to be maintained to operate properly.
  • Reduced chemical smell: Saltwater pools still use chlorine as a disinfectant but the levels are usually lower which means there’s a reduced chemical smell.
  • Gentler on skin and eyes: The lower concentration of chlorine generated in saltwater pools is less irritating to the skin and eyes compared to traditional chlorinated pools.

Cons

  • Initial cost of installation: Installing a salt chlorine generator involves an upfront investment which can be significant.
  • Salt levels need monitoring: The salt chlorine generator requires cleaning and potential replacement over time.
  • Potential system failures: Like any electronic or mechanical device, salt chlorine generators can experience issues over time due to improper maintenance, age and wear, or electrical problems.
  • Not completely chemical free: While saltwater pools don’t rely as heavily on chlorine, chlorine is still necessary for sanitisation and preventing contamination.
Pro and Cons of Pool Water

Mineral Pools

Pros

  • Low maintenance: Mineral pools are considered low maintenance due to the reduced need for chemical balancing, its gentle sanitisation, and automated systems.
  • Gentler on skin and eyes: Mineral pools are gentler on the skin and eyes compared to chlorinated water. The minerals help moisturise the skin and reduce irritation.
  • Reduced chemical use: Mineral pools require less chlorine or other harsh chemicals to maintain clean and clear water.
  • Improved water quality: Minerals like magnesium can help the flocculation process, making it easier to filter out impurities. This can lead to clearer and higher quality pool water.

Cons

  • Initial setup cost: Installing a mineral pool system and purchasing the minerals can cost more than traditional chlorine pool systems. 
  • Compatibility issues: Some mineral systems might cause issues with certain types of pool equipment or surfaces over time, particularly as high concentrations can lead to deposits or corrosion. 
  • Limited effectiveness against algae: While magnesium and copper can inhibit algae growth and reduce the need for traditional chemicals, mineral pools are not immune to algae.
  • Replacement costs: If your mineral pool system is damaged, old or is underperforming, you may need to spend money to have it replaced.

Managing Pool Water Chemistry

Managing Pool Water Chemistry

Chlorine Levels

Maintaining the proper chlorine levels in your pool is essential for killing bacteria and keeping the water clean. The ideal chlorine level for a traditional swimming pool is typically between one and 3 ppm and between 0.5 and one ppm for a mineral pool. Of course, the ideal chlorine level also depends on the size of your pool, how much it is used, temperature and the specific type of mineral system in use.

pH Balance

The pH level of your pool water indicates its acidity or basicity which impacts chlorine effectiveness and swimmer comfort. The ideal pH range for pool water is between 7.2 and 7.8. Maintaining the proper pH balance is crucial for preventing skin and eye irritation and protecting the pool equipment from corrosion.

If the pH is too low, it can cause corrosion and irritate swimmers’ eyes and skin. You can use a pH increaser (soda ash) to raise the pH levels. On the other hand, if the pH is too high, it can cause scaling and reduce chlorine effectiveness. You can lower the pH levels by using a pH decrease (muriatic acid or sodium bisulfate).

Alkalinity and Calcium Hardness

In addition to chlorine levels and pH balance, it’s important to monitor the total alkalinity and calcium hardness of your pool water. Alkalinity helps to stabilise the pH level, while calcium hardness prevents the water from becoming too corrosive. High alkalinity (high pH) can cause calcium scaling, making surfaces rough and reducing the efficiency of filters and heaters. 

To increase alkalinity, products like sodium bicarbonate are effective. You can also use muriatic acid to decrease high alkalinity, but be sure to carefully follow the instructions to avoid drastically lowering the pH. Similarly with calcium hardness, you can increase the levels with a specific product. To lower calcium levels, you can simply dilute the pool water with fresh water or use a commercial product.

Testing and Maintaining Pool Water

A man cleaning swimming pool in summer

Regularly testing your pool water is essential for ensuring that the chemical levels are balanced. The testing methods and maintenance routines will differ depending on the type of pool water you have.

Chlorinated pools

It’s important to test your pool’s chlorine and pH levels at least twice a week under normal use to make sure it’s within the ideal range of one and 3 ppm. You can test the levels by using test kits and strips, or digital tests which can provide accurate readings for chlorine, pH, and other parameters. 

It’s also recommended to perform a shock treatment once a week to break down chloramines and other contaminants. This will keep the pool water clear and prevent algae growth.

Other routine maintenance tips include regular cleaning, filter maintenance, running the pump to test circulation, and having a professional pool service conduct an annual inspection.

Saltwater pools

It’s recommended to test the chlorine and pH levels at least once a week, and the salinity, stabiliser, alkalinity and calcium hardness levels monthly. You can test these levels using the same methods and tools as you would with chlorinated pools.

While ideal levels can depend on the salt chlorine generator, the ideal salinity level for most saltwater pools is between 2700 and 4500 ppm. Total alkalinity should be kept between 80 and 120 ppm, calcium hardness between 200 and 400 ppm, and the stabiliser levels are typically 70 to 80 ppm for saltwater pools.

Routine maintenance is similar to that of chlorinated pools, except you will need to inspect and clean the salt cell to avoid calcium buildup or other debris.

Mineral pools

Maintaining a mineral pool involves keeping mineral levels balanced, ensuring water chemistry is within the proper ranges, and regular cleaning and filtration.

It’s suggested to test your pool’s pH, alkalinity, and sanitiser levels at least once a week. For mineral concentrations and other parameters, testing can be done monthly or as recommended by the manufacturer. While you can use test kits and strips, some mineral systems may require specific tests.

Maintenance tasks may include monitoring and adjusting water chemistry and mineral levels, cleaning and filter maintenance, occasional shock treatment, and professional inspections.

Conclusion

Understanding and managing pool water chemistry

Understanding and managing pool water chemistry is essential for every pool owner. By staying on top of the chlorine levels, pH balance, alkalinity, and calcium hardness, you can ensure a clean and safe swimming environment for everyone to enjoy. If you’re considering installing a pool, the team at Premium Glass supplies and installs glass pool fences. We also provide temporary fencing so you can enjoy your pool even during installation. Request a FREE quote today and we will get back to you within 24 hours. Alternatively, feel free to contact us if you have any questions as we would be more than happy to offer you some professional advice.

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