Can You Use Pool Chlorine in a Spa? Understanding the Differences in Water Treatment

At Trueform Spas, we know how important it is to ensure that your spa pool remains clean, safe, and relaxing for everyone. One common question we often get from spa pool owners is: “Can I use pool chlorine in my spa?” While both pools and spas need chemicals to sanitise the water, pool chlorine and spa-specific chemicals aren’t interchangeable. Understanding why pool chlorine isn’t suited for your spa will help you make informed decisions that protect both your water quality and your spa’s longevity.

The Basics of Pool Chlorine and Spa Chemicals

• What Is Pool Chlorine?
  Pool chlorine is one of the most common sanitisers for swimming pools. It’s highly effective at eliminating harmful bacteria, viruses, and other contaminants that thrive in pool water. Pool chlorine comes in granular, liquid, or tablet form, and it’s specifically designed to sanitise larger bodies of water—usually tens of thousands of litres.

• What Makes Spa Chemicals Different?
  Spa-specific chemicals are formulated to work effectively with the smaller water volume of spa pools and the higher water temperatures. These include spa chlorine, bromine, and other sanitising agents designed to maintain the delicate balance of spa water, keeping it safe and comfortable for users. At Trueform Spas, we always recommend using spa-specific products to ensure your spa performs at its best.

Why You Shouldn’t Use Pool Chlorine in a Spa

The main reason we advise against using pool chlorine in a spa is the difference in water volume and chemical concentration between the two. Pools typically hold between 40,000 to 100,000 litres of water, whereas spa pools generally only contain 1,000 to 2,000 litres. Because of this, the concentration of chemicals needed is significantly different.

• Chlorine Levels and Parts Per Million (ppm)
  Chlorine levels in water are measured in parts per million (ppm), indicating the amount of chlorine present relative to the total water volume. Pools usually maintain a chlorine level of 1-3 ppm, while spa pools require a chlorine concentration of 2-4 ppm due to the smaller water volume. However, adding the same amount of chlorine used for a pool into a spa would cause a much higher ppm level, leading to over-chlorination, which could result in skin irritation, eye discomfort, or even respiratory issues.

At Trueform Spas, we often remind our customers that over-chlorination isn’t just about comfort—it can also affect the performance of your spa equipment.

Temperature Considerations

Another key difference is that spa pools typically operate at higher temperatures, between 37°C and 40°C, compared to swimming pools, which are usually much cooler. The higher temperature in spas accelerates chemical reactions, causing chlorine to dissipate more quickly. Pool chlorine, designed for cooler and larger bodies of water, may not be able to maintain the proper balance in your spa, making it harder to keep your water clean and safe.

Impact on Spa Equipment and Surfaces

At Trueform Spas, we care about helping you protect your investment, and using pool chlorine in a spa can have some unwanted consequences for your spa’s equipment and surfaces. Pool chlorine is typically more potent and corrosive, which can lead to quicker wear and tear on your spa's essential components.

• Pump and Heater Damage
  The pump and heater are crucial for keeping your spa running smoothly. The higher concentration of pool chlorine can cause accelerated corrosion to these parts, reducing their efficiency and shortening their lifespan. The pump works hard to circulate water, and if it's exposed to harsh chemicals, it might become less effective over time. Similarly, the heater—constantly in contact with water—can suffer from scaling, corrosion, or even failure.

• Jet Functionality
  Spa jets are another important feature that you’ll want to protect. Trueform Spas customers love the soothing water jets for relaxation, but if pool chlorine is used, it can lead to mineral build-up or scaling inside the jets. This might reduce water flow, making the massage less effective and potentially leading to clogged or malfunctioning jets. Regular use of spa-specific chemicals helps prevent these issues.

• Surface Degradation
  The surface of your spa is also at risk if exposed to pool chlorine. Over time, the high concentration of chlorine can react with the surface material, leading to discolouration, pitting, or cracking. This not only affects the look of your spa but could also lead to more significant issues, such as leaks or compromised structural integrity. By using gentler, spa-specific products, you can keep your spa looking great and functioning optimally.

Best Practices for Maintaining Clean and Safe Spa Water

At Trueform Spas, we always encourage our customers to follow best practices to keep their spa pools clean, safe, and enjoyable for all. Here are some helpful tips to ensure your spa water stays in top condition:

• Use Spa-Specific Sanitising Products: Always choose chemicals that are formulated specifically for spa pools. These are designed to work at higher temperatures and are less likely to damage your equipment or surfaces.

• Test the Water Regularly: Regularly test your spa water to ensure that the pH, chlorine, or bromine levels remain within the recommended range. This helps keep the chemical balance right, preventing any issues before they arise.

• Clean and Replace Filters: Spa pool filters play an important role in keeping your water clean by trapping debris and contaminants. Make sure to clean and replace your filters as needed to keep your spa running efficiently.

Shock Your Spa Pool Regularly: Shocking your spa pool is a critical step in water maintenance. This process involves adding a higher dose of a sanitising agent to break down organic contaminants and restore the water's clarity. At Trueform Spas, we recommend shocking your spa at least once a week, or more frequently if it’s used regularly.