What is Pool Temperature: All You Need to Know

Temperature is a physical factor that affects water balance. It becomes significant under extreme conditions, such as in spas with high water temperatures (up to 104°F). Temperature is also a factor represented in the Saturation Index, which affects water chemistry. It can influence the growth of algae in pool water and affect the readings of ORP. In terms of equipment, temperature is sensed and controlled by devices such as thermostats and potentiometers in pool or spa heaters.

What is the Desired Pool Temperature?

The desired pool temperature is 85°F (29°C). This is particularly true if you aim to swim in spring or fall when the average water temperature is 50°F (10°C). The desired temperature can be achieved by heating the pool, which results in a 35°F (19°C) increase, significantly higher than the average. The desired temperature during the normal filtration cycle is also a factor in sizing pool heaters. However, the desired swimming season length and temperature can influence the decision to invest in a solar heating system for your pool. If you don’t heat your pool, the water temperature will match the average air temperature.

How Long Does It Take to Heat My Pool?

With solar or gas heaters, you’ll feel warm water immediately. Depending on the pool size and heater capacity, you can make the pool swimmable within a day, especially with a cover.  This is because pool heaters function by allowing water to pass through them, typically increasing the water temperature by around 10°F (6°C) before it returns to the pool. Both systems require multiple water passes through the heater, each time raising the temperature until the overall desired temperature is reached. The speed of heating can be determined using the formula: Heater Btu output/(gallons × 8.33) = degrees temperature rise/hour. For example, for a 13,500 gallons pool with a 175,000 input Btu heater, you might expect a 9°F rise in temperature in 8 hours of circulation.

How Does Temperature Influence Water Chemistry?

Temperature plays a significant role in water chemistry, particularly in the growth of algae. In places like Malibu, where pool water temperatures can vary from below 60°F in winter to 70°F in summer, the influence of temperature on water chemistry is evident. When the temperature is below 65°F, the growth of algae is minimal. However, when the temperature rises above this level, controlling algae growth becomes a constant challenge. This is because algae, like many other organisms, thrive in warmer temperatures. Therefore, maintaining an appropriate water temperature is crucial in managing water chemistry.

Does Temperature Affect ORP?

Yes, as the temperature increases, the ORP reading goes up. However, as the pH, cyanuric acid, and TDS increase, the ORP goes down.  This means that temperature has a direct impact on the Oxidation Reduction Potential (ORP) readings. When the temperature rises, the ORP reading also increases. On the other hand, an increase in pH, cyanuric acid, and Total Dissolved Solids (TDS) causes a decrease in the ORP reading. Therefore, it is crucial to consider these factors when interpreting ORP readings.

How does temperature affect water balance?

Temperature is a physical factor that affects water balance. It becomes significant under extreme conditions, such as in spas with high water temperatures (up to 104°F).  Temperature influences water chemistry, which is a key component of water balance. For instance, in pools, algae growth is minimal below 65°F but becomes a constant battle above this temperature. High water temperatures can increase the risk of scaling, while low temperatures can lead to corrosive conditions. Additionally, as the temperature increases, the ORP (Oxidation Reduction Potential) reading goes up, affecting the overall water balance. Therefore, maintaining an ideal temperature is crucial for maintaining water balance.